matrix_sdk/authentication/oauth/qrcode/

grant.rs

// Copyright 2025, 2026 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::time::Duration;

use eyeball::SharedObservable;
use futures_core::Stream;
use matrix_sdk_base::{
    boxed_into_future,
    crypto::types::{
        SecretsBundle,
        qr_login::{QrCodeData, QrCodeIntent},
    },
};
use oauth2::VerificationUriComplete;
use ruma::time::Instant;
use url::Url;
#[cfg(doc)]
use vodozemac::ecies::CheckCode;

use super::{
    LoginProtocolData, LoginProtocolType, QrAuthMessage,
    secure_channel::{EstablishedSecureChannel, SecureChannel},
};
use crate::{
    Client,
    authentication::oauth::qrcode::{
        CheckCodeSender, CloneableSender, ContinuationMessage, ContinuationMessageSender,
        GeneratedQrProgress, LoginFailureReason, QRCodeGrantLoginError, QrProgress,
        SecureChannelError, messages::LoginProtocolsMessage, secure_channel::ChannelVariant,
    },
};

async fn export_secrets_bundle(client: &Client) -> Result<SecretsBundle, QRCodeGrantLoginError> {
    let secrets_bundle = client
        .olm_machine()
        .await
        .as_ref()
        .ok_or_else(|| QRCodeGrantLoginError::MissingSecretsBackup(None))?
        .store()
        .export_secrets_bundle()
        .await?;
    Ok(secrets_bundle)
}

async fn finish_login_grant<Q>(
    client: &Client,
    channel: &mut EstablishedSecureChannel,
    device_creation_timeout: Duration,
    secrets_bundle: &SecretsBundle,
    state: &SharedObservable<GrantLoginProgress<Q>>,
) -> Result<(), QRCodeGrantLoginError> {
    // The new device registers with the authorization server and sends it a
    // device authorization authorization request.
    //
    // -- MSC4108 OAuth 2.0 login step 2

    // We wait for the new device to send us the m.login.protocol message with
    // the device authorization grant information.
    //
    // -- MSC4108 OAuth 2.0 login step 3
    let (protocol, device_id) = match channel.receive_json().await? {
        QrAuthMessage::LoginProtocol { protocol, device_id } => (protocol, device_id),
        QrAuthMessage::LoginFailure { reason, .. } => {
            return Err(QRCodeGrantLoginError::LoginFailure { reason });
        }
        message => {
            return Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.protocol",
                received: Box::new(message),
            });
        }
    };

    // We verify the selected protocol, and that its data uses the layout of
    // our channel variant.
    //
    // -- MSC4108 OAuth 2.0 login step 4
    let device_authorization_grant = match channel.channel_variant() {
        ChannelVariant::Msc4108 => match protocol {
            LoginProtocolData::Msc4108DeviceAuthorizationGrant(device_authorization_grant) => {
                Ok(device_authorization_grant)
            }
            protocol => Err(protocol),
        },
        #[cfg(feature = "unstable-msc4388")]
        ChannelVariant::Msc4388 => match protocol {
            LoginProtocolData::Msc4388DeviceAuthorizationGrant(device_authorization_grant) => {
                Ok(device_authorization_grant)
            }
            protocol => Err(protocol),
        },
    };

    let device_authorization_grant = match device_authorization_grant {
        Ok(device_authorization_grant) => device_authorization_grant,
        // The device authorization grant, but using the layout of the other
        // channel variant.
        Err(
            protocol @ (LoginProtocolData::Msc4108DeviceAuthorizationGrant(_)
            | LoginProtocolData::Msc4388DeviceAuthorizationGrant(_)),
        ) => {
            channel
                .send_json(QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::UnexpectedMessageReceived,
                    homeserver: None,
                })
                .await?;
            return Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.protocol",
                received: Box::new(QrAuthMessage::LoginProtocol { protocol, device_id }),
            });
        }
        Err(protocol) => {
            channel
                .send_json(QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::UnsupportedProtocol,
                    homeserver: None,
                })
                .await?;
            return Err(QRCodeGrantLoginError::UnsupportedProtocol(protocol.protocol()));
        }
    };

    // We check that the device ID is still available.
    //
    // -- MSC4108 OAuth 2.0 login step 4 continued
    if !matches!(client.device_exists(device_id.clone().into()).await, Ok(false)) {
        channel
            .send_json(QrAuthMessage::LoginFailure {
                reason: LoginFailureReason::DeviceAlreadyExists,
                homeserver: None,
            })
            .await?;
        return Err(QRCodeGrantLoginError::DeviceIDAlreadyInUse);
    }

    // We emit an update so that the caller can open the verification URI in a
    // system browser to consent to the login.
    //
    // -- MSC4108 OAuth 2.0 login step 4 continued
    let verification_uri = Url::parse(
        device_authorization_grant
            .verification_uri_complete
            .map(VerificationUriComplete::into_secret)
            .unwrap_or(device_authorization_grant.verification_uri.to_string())
            .as_str(),
    )
    .map_err(|e| QRCodeGrantLoginError::Unknown(e.to_string()))?;

    // We send the new device the m.login.protocol_accepted message to let it
    // know that the consent process is in progress.
    //
    // -- MSC4108 OAuth 2.0 login step 4 continued
    let message = QrAuthMessage::LoginProtocolAccepted;
    channel.send_json(&message).await?;

    let (sender, receiver) = tokio::sync::oneshot::channel();
    state.set(GrantLoginProgress::WaitingForAuth {
        verification_uri,
        continuation_sender: ContinuationMessageSender(CloneableSender::new(sender)),
    });

    // We wait for this device to confirm that the authorization using the
    // verification URI has succeeded.
    match receiver.await {
        Ok(ContinuationMessage::Confirm) => {}
        Ok(ContinuationMessage::Cancel) | Err(_) => {
            channel
                .send_json(QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::UserCancelled,
                    homeserver: None,
                })
                .await?;
            return Err(QRCodeGrantLoginError::LoginFailure {
                reason: LoginFailureReason::UserCancelled,
            });
        }
    }

    // The new device displays the user code it received from the authorization
    // server and starts polling for an access token. In parallel, the user
    // consents to the new login in the browser on this device, while verifying
    // the user code displayed on the other device.
    //
    // -- MSC4108 OAuth 2.0 login steps 5 & 6

    // We wait for the new device to send us the m.login.success or
    // m.login.failure message
    match channel.receive_json().await? {
        QrAuthMessage::LoginSuccess => (),
        QrAuthMessage::LoginFailure { reason, .. } => {
            return Err(QRCodeGrantLoginError::LoginFailure { reason });
        }
        message => {
            return Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.success",
                received: Box::new(message),
            });
        }
    }

    // We check that the new device was created successfully, allowing for the
    // specified delay.
    //
    // -- MSC4108 Secret sharing and device verification step 1
    let deadline = Instant::now() + device_creation_timeout;

    loop {
        if matches!(client.device_exists(device_id.clone().into()).await, Ok(true)) {
            break;
        } else {
            // If the deadline hasn't yet passed, give it some time and retry
            // the request.
            if Instant::now() < deadline {
                matrix_sdk_common::sleep::sleep(Duration::from_millis(500)).await;
                continue;
            } else {
                // The deadline has passed. Let's fail the login process.
                channel
                    .send_json(QrAuthMessage::LoginFailure {
                        reason: LoginFailureReason::DeviceNotFound,
                        homeserver: None,
                    })
                    .await?;
                return Err(QRCodeGrantLoginError::DeviceNotFound);
            }
        }
    }

    // We send the new device the secrets bundle.
    //
    // -- MSC4108 Secret sharing and device verification step 2
    state.set(GrantLoginProgress::SyncingSecrets);
    let message = QrAuthMessage::LoginSecrets(secrets_bundle.clone());
    channel.send_json(&message).await?;

    // And we're done.
    state.set(GrantLoginProgress::Done);

    Ok(())
}

/// The progress of granting the login.
#[derive(Clone, Debug, Default)]
pub enum GrantLoginProgress<Q> {
    /// We're just starting up, this is the default and initial state.
    #[default]
    Starting,
    /// The secure channel is being established by exchanging the QR code and/or
    /// [`CheckCode`].
    EstablishingSecureChannel(Q),
    /// The secure channel has been confirmed using the [`CheckCode`] and this
    /// device is waiting for the authorization to complete.
    WaitingForAuth {
        /// A URI to open in a (secure) system browser to verify the new login.
        verification_uri: Url,
        /// A sender to confirm that the verification URI has been opened in
        /// the browser and the application is ready to proceed, or to cancel.
        ///
        /// The new device has already been told to proceed when this state is
        /// emitted, so confirming only resumes this side of the process. This
        /// allows applications that suspend or navigate away while the
        /// verification URI is open to resume explicitly.
        continuation_sender: ContinuationMessageSender,
    },
    /// The new device has been granted access and this device is sending the
    /// secrets to it.
    SyncingSecrets,
    /// The process is complete.
    Done,
}

/// Named future for granting login by scanning a QR code on this, existing,
/// device that was generated by the other, new, device.
#[derive(Debug)]
pub struct GrantLoginWithScannedQrCode {
    client: Client,
    qr_code_data: QrCodeData,
    device_creation_timeout: Duration,
    state: SharedObservable<GrantLoginProgress<QrProgress>>,
}

impl GrantLoginWithScannedQrCode {
    pub(crate) fn new(
        client: &Client,
        qr_code_data: &QrCodeData,
        device_creation_timeout: Duration,
    ) -> GrantLoginWithScannedQrCode {
        GrantLoginWithScannedQrCode {
            client: client.clone(),
            qr_code_data: qr_code_data.clone(),
            device_creation_timeout,
            state: Default::default(),
        }
    }
}

impl GrantLoginWithScannedQrCode {
    /// Subscribe to the progress of QR code login.
    ///
    /// It's necessary to subscribe to this to capture the [`CheckCode`] in
    /// order to display it to the other device and to obtain the verification
    /// URL for consenting to the login.
    pub fn subscribe_to_progress(
        &self,
    ) -> impl Stream<Item = GrantLoginProgress<QrProgress>> + use<> {
        self.state.subscribe()
    }
}

impl IntoFuture for GrantLoginWithScannedQrCode {
    type Output = Result<(), QRCodeGrantLoginError>;
    boxed_into_future!();

    fn into_future(self) -> Self::IntoFuture {
        Box::pin(async move {
            // Before we get here, the other device has created a new rendezvous
            // session and presented a QR code which this device has scanned.
            //
            // -- MSC4108 Secure channel setup steps 1-3

            // First things first, export the secrets bundle and establish the
            // secure channel. Since we're the one that scanned the QR code,
            // we're certain that the secure channel is secure, under the
            // assumption that we didn't scan the wrong QR code.
            //
            // -- MSC4108 Secure channel setup steps 3-5
            let secrets_bundle = export_secrets_bundle(&self.client).await?;

            let mut channel = EstablishedSecureChannel::from_qr_code(
                self.client.inner.http_client.inner.clone(),
                &self.qr_code_data,
                QrCodeIntent::Reciprocate,
            )
            .await?;

            // The other side isn't yet sure that it's talking to the right
            // device, show a check code so they can confirm.
            //
            // -- MSC4108 Secure channel setup step 6
            let check_code = channel.check_code().to_owned();
            self.state
                .set(GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }));

            // The user now enters the checkcode on the other device which
            // verifies it and will only continue requesting the login if the
            // code matches.
            //
            // -- MSC4108 Secure channel setup step 7

            // Inform the other device about the available login protocols and
            // the homeserver to use.
            //
            // -- MSC4108 OAuth 2.0 login step 1
            let message = match channel.channel_variant() {
                ChannelVariant::Msc4108 => {
                    QrAuthMessage::LoginProtocols(LoginProtocolsMessage::Msc4108 {
                        protocols: vec![LoginProtocolType::DeviceAuthorizationGrant],
                        homeserver: self.client.homeserver(),
                    })
                }
                #[cfg(feature = "unstable-msc4388")]
                ChannelVariant::Msc4388 => {
                    QrAuthMessage::LoginProtocols(LoginProtocolsMessage::Msc4388 {
                        protocols: vec![LoginProtocolType::DeviceAuthorizationGrant],
                        base_url: self.client.homeserver(),
                    })
                }
            };
            channel.send_json(message).await?;

            // Proceed with granting the login.
            //
            // -- MSC4108 OAuth 2.0 login remaining steps
            finish_login_grant(
                &self.client,
                &mut channel,
                self.device_creation_timeout,
                &secrets_bundle,
                &self.state,
            )
            .await
        })
    }
}

/// Named future for granting login by generating a QR code on this, existing,
/// device to be scanned by the other, new, device.
#[derive(Debug)]
pub struct GrantLoginWithGeneratedQrCode {
    client: Client,
    device_creation_timeout: Duration,
    state: SharedObservable<GrantLoginProgress<GeneratedQrProgress>>,
    msc_4388_support: bool,
}

impl GrantLoginWithGeneratedQrCode {
    pub(crate) fn new(
        client: &Client,
        device_creation_timeout: Duration,
    ) -> GrantLoginWithGeneratedQrCode {
        GrantLoginWithGeneratedQrCode {
            client: client.clone(),
            device_creation_timeout,
            state: Default::default(),
            msc_4388_support: false,
        }
    }
}

impl GrantLoginWithGeneratedQrCode {
    /// Subscribe to the progress of QR code login.
    ///
    /// It's necessary to subscribe to this to capture the QR code in order to
    /// display it to the other device, to feed the [`CheckCode`] entered by the
    /// user back in and to obtain the verification URL for consenting to the
    /// login.
    pub fn subscribe_to_progress(
        &self,
    ) -> impl Stream<Item = GrantLoginProgress<GeneratedQrProgress>> + use<> {
        self.state.subscribe()
    }

    /// Enable and generate a QR code which supports [MSC4388].
    ///
    /// [MSC4388]: https://github.com/matrix-org/matrix-spec-proposals/pull/4388
    #[cfg(feature = "unstable-msc4388")]
    pub fn with_msc4388_support(&mut self) -> &mut Self {
        self.msc_4388_support = true;
        self
    }
}

impl IntoFuture for GrantLoginWithGeneratedQrCode {
    type Output = Result<(), QRCodeGrantLoginError>;
    boxed_into_future!();

    fn into_future(self) -> Self::IntoFuture {
        Box::pin(async move {
            // Create a new ephemeral key pair and a rendezvous session to grant
            // a login with.
            //
            // -- MSC4108 Secure channel setup steps 1 & 2
            let secrets_bundle = export_secrets_bundle(&self.client).await?;
            let channel = SecureChannel::reciprocate(&self.client, self.msc_4388_support).await?;

            // Extract the QR code data and emit an update so that the caller
            // can present the QR code for scanning by the new device.
            //
            // -- MSC4108 Secure channel setup step 3
            self.state.set(GrantLoginProgress::EstablishingSecureChannel(
                GeneratedQrProgress::QrReady(channel.qr_code_data().clone()),
            ));

            // Wait for the secure channel to connect. The other device now
            // needs to scan the QR code and send us the LoginInitiateMessage
            // which we respond to with the LoginOkMessage.
            //
            // -- MSC4108 step 4 & 5
            let channel = channel.connect().await?;

            // The other device now needs to verify our message, compute the
            // checkcode and display it. We emit a progress update to let the
            // caller prompt the user to enter the checkcode and feed it back to
            // us.
            //
            // -- MSC4108 Secure channel setup step 6
            let (tx, rx) = tokio::sync::oneshot::channel();
            self.state.set(GrantLoginProgress::EstablishingSecureChannel(
                GeneratedQrProgress::QrScanned(CheckCodeSender::new(tx)),
            ));
            let check_code = rx.await.map_err(|_| SecureChannelError::CannotReceiveCheckCode)?;

            // Use the checkcode to verify that the channel is actually
            // secure.
            //
            // -- MSC4108 Secure channel setup step 7
            let mut channel = channel.confirm(check_code)?;

            // Inform the other device about the available login protocols and
            // the homeserver to use. The MSC requires this message to always be
            // sent first, but we only do so for the MSC4388 variant: with the
            // MSC4108 variant the new device derives the homeserver from the
            // QR code and doesn't expect this message, so we skip it to stay
            // compatible with existing implementations.
            //
            // -- MSC4108 OAuth 2.0 login step 1
            match channel.channel_variant() {
                ChannelVariant::Msc4108 => {}
                #[cfg(feature = "unstable-msc4388")]
                ChannelVariant::Msc4388 => {
                    let message = QrAuthMessage::LoginProtocols(LoginProtocolsMessage::Msc4388 {
                        protocols: vec![LoginProtocolType::DeviceAuthorizationGrant],
                        base_url: self.client.homeserver(),
                    });
                    channel.send_json(message).await?;
                }
            }

            // Proceed with granting the login.
            //
            // -- MSC4108 OAuth 2.0 login remaining steps
            finish_login_grant(
                &self.client,
                &mut channel,
                self.device_creation_timeout,
                &secrets_bundle,
                &self.state,
            )
            .await
        })
    }
}

#[cfg(all(test, not(target_family = "wasm")))]
mod test {
    use std::{assert_matches, sync::Arc};

    use futures_util::StreamExt;
    use matrix_sdk_base::{
        CancellableIntoFutureExt,
        crypto::types::{SecretsBundle, qr_login::QrCodeIntentData},
    };
    use matrix_sdk_common::executor::spawn;
    use matrix_sdk_test::async_test;
    use oauth2::{EndUserVerificationUrl, VerificationUriComplete};
    use ruma::{owned_device_id, owned_user_id};
    use strass::assert_let;
    use tokio::sync::oneshot;
    use tracing::debug;

    use super::*;
    use crate::{
        authentication::oauth::qrcode::{
            LoginFailureReason, MessageDecodeError, QrAuthMessage,
            messages::AuthorizationGrant,
            secure_channel::{EstablishedSecureChannel, test::MockedRendezvousServer},
        },
        test_utils::mocks::MatrixMockServer,
    };

    enum BobBehaviour {
        HappyPath,
        UnexpectedMessageInsteadOfLoginProtocol,
        LoginFailureInsteadOfLoginProtocol,
        UnexpectedMessageInsteadOfLoginSuccess,
        LoginFailureInsteadOfLoginSuccess,
        DeviceAlreadyExists,
        DeviceNotCreated,
        InvalidJsonMessage,
        /// Alice cancels after Bob signals that he received
        /// `m.login.protocol_accepted`.
        CancelledWhileWaitingForAuth(oneshot::Sender<()>),
        UnsupportedProtocol,
        UnsupportedProtocolWithDeviceAuthorizationGrant,
        MissingDeviceAuthorizationGrant,
        MismatchedDeviceAuthorizationGrantLayout,
    }

    #[allow(clippy::too_many_arguments)]
    async fn request_login_with_scanned_qr_code(
        behaviour: BobBehaviour,
        qr_code_rx: oneshot::Receiver<QrCodeData>,
        check_code_tx: oneshot::Sender<u8>,
        server: Option<MatrixMockServer>,
        // The rendezvous server is here because it contains MockGuards that are
        // tied to the lifetime of the MatrixMockServer. Otherwise we might
        // attempt to drop the MatrixMockServer before the MockGuards.
        _rendezvous_server: &MockedRendezvousServer,
        device_authorization_grant: Option<AuthorizationGrant>,
        secrets_bundle: Option<SecretsBundle>,
    ) {
        // Wait for Alice to produce the qr code.
        let qr_code_data = qr_code_rx.await.expect("Bob should receive the QR code");

        // Use the QR code to establish the secure channel from the new client
        // (Bob).
        let mut bob = EstablishedSecureChannel::from_qr_code(
            reqwest::Client::new(),
            &qr_code_data,
            QrCodeIntent::Login,
        )
        .await
        .expect("Bob should be able to connect the secure channel");

        // Let Alice know about the checkcode so she can verify the channel.
        check_code_tx.send(bob.check_code()).expect("Bob should be able to send the checkcode");

        // With MSC4388, Alice informs us about the available login protocols
        // even though we already know the homeserver from the QR code.
        if let QrCodeIntentData::Msc4388 { base_url: qr_base_url, .. } = qr_code_data.intent_data()
        {
            let message = bob
                .receive_json()
                .await
                .expect("Bob should receive the LoginProtocols message from Alice");

            assert_let!(
                QrAuthMessage::LoginProtocols(LoginProtocolsMessage::Msc4388 {
                    protocols,
                    base_url,
                }) = message
            );

            assert_eq!(protocols, vec![LoginProtocolType::DeviceAuthorizationGrant]);
            assert_eq!(&base_url, qr_base_url.as_url());
        }

        match behaviour {
            BobBehaviour::UnexpectedMessageInsteadOfLoginProtocol => {
                // Send an unexpected message and exit.
                let message = QrAuthMessage::LoginSuccess;
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::LoginFailureInsteadOfLoginProtocol => {
                // Send a LoginFailure message instead of LoginProtocol.
                let message = QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::UserCancelled,
                    homeserver: None,
                };
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::InvalidJsonMessage => {
                // Send invalid JSON that cannot be deserialized as
                // QrAuthMessage.
                bob.send_json(serde_json::json!({"type": "m.login.bogus"})).await.unwrap();
                return;
            }
            BobBehaviour::DeviceAlreadyExists => {
                // Mock the endpoint for querying devices so that Alice thinks
                // the device already exists.
                server
                    .as_ref()
                    .expect("Bob needs the server for DeviceAlreadyExists")
                    .mock_get_device()
                    .ok()
                    .expect(1..)
                    .named("get_device")
                    .mount()
                    .await;

                // Now send the LoginProtocol message.
                let message = QrAuthMessage::LoginProtocol {
                    protocol: LoginProtocolData::device_authorization_grant(
                        device_authorization_grant
                            .expect("Bob needs the device authorization grant"),
                        bob.channel_variant(),
                    ),
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();

                // Alice should fail the login with the appropriate reason.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::DeviceAlreadyExists);

                return; // Exit.
            }
            BobBehaviour::UnsupportedProtocol => {
                // Request a protocol that Alice did not offer.
                bob.send_json(serde_json::json!({
                    "type": "m.login.protocol",
                    "protocol": "m.unknown_protocol",
                    "device_id": "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4",
                }))
                .await
                .unwrap();

                // Alice should reject the protocol.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::UnsupportedProtocol);

                return; // Exit.
            }
            BobBehaviour::UnsupportedProtocolWithDeviceAuthorizationGrant => {
                // Request a protocol that Alice did not offer, while also
                // including a device authorization grant.
                bob.send_json(serde_json::json!({
                    "type": "m.login.protocol",
                    "protocol": "m.unknown_protocol",
                    "device_authorization_grant": device_authorization_grant
                        .expect("Bob needs the device authorization grant"),
                    "device_id": "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4",
                }))
                .await
                .unwrap();

                // Alice should reject the protocol, regardless of the device
                // authorization grant.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::UnsupportedProtocol);

                return; // Exit.
            }
            BobBehaviour::MissingDeviceAuthorizationGrant => {
                // Request the device authorization grant protocol without
                // including the device authorization grant.
                bob.send_json(serde_json::json!({
                    "type": "m.login.protocol",
                    "protocol": "device_authorization_grant",
                    "device_id": "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4",
                }))
                .await
                .unwrap();

                return;
            }
            BobBehaviour::MismatchedDeviceAuthorizationGrantLayout => {
                // Send the device authorization grant with the layout of the
                // other channel variant.
                let device_authorization_grant =
                    device_authorization_grant.expect("Bob needs the device authorization grant");
                let protocol = match bob.channel_variant() {
                    ChannelVariant::Msc4108 => LoginProtocolData::Msc4388DeviceAuthorizationGrant(
                        device_authorization_grant,
                    ),
                    #[cfg(feature = "unstable-msc4388")]
                    ChannelVariant::Msc4388 => LoginProtocolData::Msc4108DeviceAuthorizationGrant(
                        device_authorization_grant,
                    ),
                };
                let message = QrAuthMessage::LoginProtocol {
                    protocol,
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();

                // Alice should reject the message.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::UnexpectedMessageReceived);

                return; // Exit.
            }
            BobBehaviour::CancelledWhileWaitingForAuth(protocol_accepted_tx) => {
                // Send the LoginProtocol message.
                let message = QrAuthMessage::LoginProtocol {
                    protocol: LoginProtocolData::device_authorization_grant(
                        device_authorization_grant
                            .expect("Bob needs the device authorization grant"),
                        bob.channel_variant(),
                    ),
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();

                // Receive the LoginProtocolAccepted message.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginProtocolAccepted message from Alice");
                assert_let!(QrAuthMessage::LoginProtocolAccepted = message);

                // Let Alice know she can cancel now.
                protocol_accepted_tx
                    .send(())
                    .expect("Bob should be able to signal that the protocol was accepted");

                // Alice cancels while waiting for the authorization and should
                // fail the login with the appropriate reason.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::UserCancelled);

                return; // Exit.
            }
            _ => {
                // Send the LoginProtocol message.
                let message = QrAuthMessage::LoginProtocol {
                    protocol: LoginProtocolData::device_authorization_grant(
                        device_authorization_grant
                            .expect("Bob needs the device authorization grant"),
                        bob.channel_variant(),
                    ),
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();
            }
        }

        // Receive the LoginProtocolAccepted message.
        let message = bob
            .receive_json()
            .await
            .expect("Bob should receive the LoginProtocolAccepted message from Alice");
        assert_let!(QrAuthMessage::LoginProtocolAccepted = message);

        match behaviour {
            BobBehaviour::UnexpectedMessageInsteadOfLoginSuccess => {
                // Send an unexpected message instead of LoginSuccess.
                let message = QrAuthMessage::LoginProtocolAccepted;
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::LoginFailureInsteadOfLoginSuccess => {
                // Send a LoginFailure message instead of LoginSuccess.
                let message = QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::AuthorizationExpired,
                    homeserver: None,
                };
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::DeviceNotCreated => {
                // Don't mock the endpoint for querying devices so that Alice
                // cannot verify that we have logged in.

                // Send the LoginSuccess message to claim that we have logged
                // in.
                let message = QrAuthMessage::LoginSuccess;
                bob.send_json(message).await.unwrap();

                // Alice should eventually give up querying our device and fail
                // the login with the appropriate reason.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::DeviceNotFound);

                return; // Exit.
            }
            _ => {
                // Mock the endpoint for querying devices so that Alice thinks
                // we have logged in.
                server
                    .as_ref()
                    .expect("Bob needs the server for HappyPath")
                    .mock_get_device()
                    .ok()
                    .expect(1..)
                    .named("get_device")
                    .mount()
                    .await;

                // Send the LoginSuccess message.
                let message = QrAuthMessage::LoginSuccess;
                bob.send_json(message).await.unwrap();
            }
        }

        // Receive the LoginSecrets message.
        let message = bob
            .receive_json()
            .await
            .expect("Bob should receive the LoginSecrets message from Alice");
        assert_let!(QrAuthMessage::LoginSecrets(bundle) = message);

        // Verify that we received the correct secrets.
        assert_eq!(
            serde_json::to_value(&secrets_bundle).unwrap(),
            serde_json::to_value(&bundle).unwrap()
        );
    }

    #[allow(clippy::too_many_arguments)]
    async fn request_login_with_generated_qr_code(
        behaviour: BobBehaviour,
        channel: SecureChannel,
        check_code_rx: oneshot::Receiver<u8>,
        server: Option<MatrixMockServer>,
        // The rendezvous server is here because it contains MockGuards that are
        // tied to the lifetime of the MatrixMockServer. Otherwise we might
        // attempt to drop the MatrixMockServer before the MockGuards.
        _rendezvous_server: &MockedRendezvousServer,
        homeserver: Url,
        device_authorization_grant: Option<AuthorizationGrant>,
        secrets_bundle: Option<SecretsBundle>,
    ) {
        let is_using_msc_4388 = match channel.qr_code_data().intent_data() {
            QrCodeIntentData::Msc4108 { .. } => false,
            QrCodeIntentData::Msc4388 { .. } => true,
        };

        // Wait for Alice to scan the qr code and connect the secure channel.
        let channel =
            channel.connect().await.expect("Bob should be able to connect the secure channel");

        // Wait for Alice to send us the checkcode and use it to verify the
        // channel.
        let check_code = check_code_rx.await.expect("Bob should receive the checkcode");
        let mut bob = channel
            .confirm(check_code)
            .expect("Bob should be able to confirm the channel is secure");

        // Receive the LoginProtocols message.
        let message = bob
            .receive_json()
            .await
            .expect("Bob should receive the LoginProtocolAccepted message from Alice");

        let (protocols, alice_homeserver) = if is_using_msc_4388 {
            assert_let!(
                QrAuthMessage::LoginProtocols(LoginProtocolsMessage::Msc4388 {
                    protocols,
                    base_url,
                }) = message
            );

            (protocols, base_url)
        } else {
            assert_let!(
                QrAuthMessage::LoginProtocols(LoginProtocolsMessage::Msc4108 {
                    protocols,
                    homeserver,
                }) = message
            );

            (protocols, homeserver)
        };

        assert_eq!(protocols, vec![LoginProtocolType::DeviceAuthorizationGrant]);
        assert_eq!(alice_homeserver, homeserver);

        match behaviour {
            BobBehaviour::UnexpectedMessageInsteadOfLoginProtocol => {
                // Send an unexpected message and exit.
                let message = QrAuthMessage::LoginSuccess;
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::LoginFailureInsteadOfLoginProtocol => {
                // Send a LoginFailure message instead of LoginProtocol.
                let message = QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::UserCancelled,
                    homeserver: None,
                };
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::InvalidJsonMessage => {
                // Send invalid JSON that cannot be deserialized as
                // QrAuthMessage.
                bob.send_json(serde_json::json!({"type": "m.login.bogus"})).await.unwrap();
                return;
            }
            BobBehaviour::DeviceAlreadyExists => {
                // Mock the endpoint for querying devices so that Alice thinks
                // the device already exists.
                server
                    .as_ref()
                    .expect("Bob needs the MatrixMockServer")
                    .mock_get_device()
                    .ok()
                    .expect(1..)
                    .named("get_device")
                    .mount()
                    .await;

                // Now send the LoginProtocol message.
                let message = QrAuthMessage::LoginProtocol {
                    protocol: LoginProtocolData::device_authorization_grant(
                        device_authorization_grant
                            .expect("Bob needs the device authorization grant"),
                        bob.channel_variant(),
                    ),
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();

                // Alice should fail the login with the appropriate reason.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::DeviceAlreadyExists);

                return; // Exit.
            }
            BobBehaviour::CancelledWhileWaitingForAuth(protocol_accepted_tx) => {
                // Send the LoginProtocol message.
                let message = QrAuthMessage::LoginProtocol {
                    protocol: LoginProtocolData::device_authorization_grant(
                        device_authorization_grant
                            .expect("Bob needs the device authorization grant"),
                        bob.channel_variant(),
                    ),
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();

                // Receive the LoginProtocolAccepted message.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginProtocolAccepted message from Alice");
                assert_let!(QrAuthMessage::LoginProtocolAccepted = message);

                // Let Alice know she can cancel now.
                protocol_accepted_tx
                    .send(())
                    .expect("Bob should be able to signal that the protocol was accepted");

                // Alice cancels while waiting for the authorization and should
                // fail the login with the appropriate reason.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::UserCancelled);

                return; // Exit.
            }
            _ => {
                // Send the LoginProtocol message.
                let message = QrAuthMessage::LoginProtocol {
                    protocol: LoginProtocolData::device_authorization_grant(
                        device_authorization_grant
                            .expect("Bob needs the device authorization grant"),
                        bob.channel_variant(),
                    ),
                    device_id: "wjLpTLRqbqBzLs63aYaEv2Boi6cFEbbM/sSRQ2oAKk4".to_owned(),
                };
                bob.send_json(message).await.unwrap();
            }
        }

        // Receive the LoginProtocolAccepted message.
        let message = bob
            .receive_json()
            .await
            .expect("Bob should receive the LoginProtocolAccepted message from Alice");
        assert_let!(QrAuthMessage::LoginProtocolAccepted = message);

        match behaviour {
            BobBehaviour::UnexpectedMessageInsteadOfLoginSuccess => {
                // Send an unexpected message instead of LoginSuccess.
                let message = QrAuthMessage::LoginProtocolAccepted;
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::LoginFailureInsteadOfLoginSuccess => {
                // Send a LoginFailure message instead of LoginSuccess.
                let message = QrAuthMessage::LoginFailure {
                    reason: LoginFailureReason::AuthorizationExpired,
                    homeserver: None,
                };
                bob.send_json(message).await.unwrap();
                return;
            }
            BobBehaviour::DeviceNotCreated => {
                // Don't mock the endpoint for querying devices so that Alice
                // cannot verify that we have logged in.

                // Send the LoginSuccess message to claim that we have logged
                // in.
                let message = QrAuthMessage::LoginSuccess;
                bob.send_json(message).await.unwrap();

                // Alice should eventually give up querying our device and fail
                // the login with the appropriate reason.
                let message = bob
                    .receive_json()
                    .await
                    .expect("Bob should receive the LoginFailure message from Alice");
                assert_let!(QrAuthMessage::LoginFailure { reason, .. } = message);
                assert_matches!(reason, LoginFailureReason::DeviceNotFound);

                return; // Exit.
            }
            _ => {
                // Mock the endpoint for querying devices so that Alice thinks
                // we have logged in.
                server
                    .as_ref()
                    .expect("Bob needs the MatrixMockServer")
                    .mock_get_device()
                    .ok()
                    .expect(1..)
                    .named("get_device")
                    .mount()
                    .await;

                // Send the LoginSuccess message.
                let message = QrAuthMessage::LoginSuccess;
                bob.send_json(message).await.unwrap();
            }
        }

        // Receive the LoginSecrets message.
        let message = bob
            .receive_json()
            .await
            .expect("Bob should receive the LoginSecrets message from Alice");
        assert_let!(QrAuthMessage::LoginSecrets(bundle) = message);

        // Verify that we received the correct secrets.
        assert_eq!(
            serde_json::to_value(&secrets_bundle).unwrap(),
            serde_json::to_value(&bundle).unwrap()
        );
    }

    async fn test_grant_login_with_generated_qr_code(msc_4388: bool) {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, msc_4388)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        #[allow(unused_mut)]
        let mut grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();

        #[cfg(feature = "unstable-msc4388")]
        if msc_4388 {
            grant.with_msc4388_support();
        }

        let secrets_bundle = export_secrets_bundle(&alice)
            .await
            .expect("Alice should be able to export the secrets bundle");
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrScanned(_)
                            )
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    GrantLoginProgress::SyncingSecrets => {
                        assert_matches!(state, GrantLoginProgress::WaitingForAuth { .. });
                    }
                    GrantLoginProgress::Done => {
                        assert_matches!(state, GrantLoginProgress::SyncingSecrets);
                        break;
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::HappyPath,
                qr_code_rx,
                checkcode_tx,
                Some(server),
                &rendezvous_server,
                Some(device_authorization_grant),
                Some(secrets_bundle),
            )
            .await;
        });

        // Wait for all tasks to finish.
        grant.await.expect("Alice should be able to grant the login");
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_msc_4108() {
        test_grant_login_with_generated_qr_code(false).await;
    }

    #[async_test]
    #[cfg(feature = "unstable-msc4388")]
    async fn test_grant_login_with_generated_qr_code_msc_4388() {
        test_grant_login_with_generated_qr_code(true).await;
    }

    async fn test_grant_login_with_scanned_qr_code(msc_4388: bool) {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, msc_4388)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, msc_4388)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let secrets_bundle = export_secrets_bundle(&alice)
            .await
            .expect("Alice should be able to export the secrets bundle");
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. })
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    GrantLoginProgress::SyncingSecrets => {
                        assert_matches!(state, GrantLoginProgress::WaitingForAuth { .. });
                    }
                    GrantLoginProgress::Done => {
                        assert_matches!(state, GrantLoginProgress::SyncingSecrets);
                        break;
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::HappyPath,
                channel,
                checkcode_rx,
                Some(server),
                &rendezvous_server,
                alice.homeserver(),
                Some(device_authorization_grant),
                Some(secrets_bundle),
            )
            .await;
        });

        // Wait for all tasks to finish.
        grant.await.expect("Alice should be able to grant the login");
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_msc_4108() {
        test_grant_login_with_scanned_qr_code(false).await;
    }

    #[async_test]
    #[cfg(feature = "unstable-msc4388")]
    async fn test_grant_login_with_scanned_qr_code_msc_4388() {
        test_grant_login_with_scanned_qr_code(true).await;
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_with_homeserver_swap() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        let login_server = MatrixMockServer::new().await;

        login_server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        login_server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        login_server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = login_server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let secrets_bundle = export_secrets_bundle(&alice)
            .await
            .expect("Alice should be able to export the secrets bundle");
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. })
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    GrantLoginProgress::SyncingSecrets => {
                        assert_matches!(state, GrantLoginProgress::WaitingForAuth { .. });
                    }
                    GrantLoginProgress::Done => {
                        assert_matches!(state, GrantLoginProgress::SyncingSecrets);
                        break;
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::HappyPath,
                channel,
                checkcode_rx,
                Some(login_server),
                &rendezvous_server,
                alice.homeserver(),
                Some(device_authorization_grant),
                Some(secrets_bundle),
            )
            .await;
        });

        // Wait for all tasks to finish.
        grant.await.expect("Alice should be able to grant the login");
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_grant_cancelled() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();

        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let grant = grant.cancellable();
        let cancel = grant.cancellation_token();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                        cancel.cancel();
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let rendezvous_server_clone = rendezvous_server.clone();
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::UnexpectedMessageInsteadOfLoginProtocol,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(grant.await, None, "Alice should abort the login by cancelling it");
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_grant_cancelled() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let grant = grant.cancellable();
        let cancel = grant.cancellation_token();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                        cancel.cancel();
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::UnexpectedMessageInsteadOfLoginProtocol,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server_clone,
                alice.homeserver(),
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(grant.await, None, "Alice should abort the login by cancelling it");
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_unexpected_message_instead_of_login_protocol()
    {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let rendezvous_server_clone = rendezvous_server.clone();
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::UnexpectedMessageInsteadOfLoginProtocol,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_let!(
            Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.protocol",
                received,
            }) = grant.await,
            "Alice should abort the login with expected error variant"
        );
        assert_matches!(
            *received,
            QrAuthMessage::LoginSuccess,
            "Alice should abort the login with expected error message"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_unexpected_message_instead_of_login_protocol() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::UnexpectedMessageInsteadOfLoginProtocol,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server_clone,
                alice.homeserver(),
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_let!(
            Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.protocol",
                received,
            }) = grant.await,
            "Alice should abort the login with expected error variant"
        );
        assert_matches!(
            *received,
            QrAuthMessage::LoginSuccess,
            "Alice should abort the login with expected error message"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    /// Let Bob send a `m.login.protocol` message that Alice rejects, and return
    /// the error Alice aborts the login with.
    async fn grant_login_with_generated_qr_code_rejected_protocol(
        behaviour: BobBehaviour,
        msc_4388: bool,
    ) -> QRCodeGrantLoginError {
        let server = MatrixMockServer::new().await;
        // Shared with Bob's task, so the rendezvous session outlives it and
        // Alice can still read Bob's last message.
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, msc_4388)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        #[allow(unused_mut)]
        let mut grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();

        #[cfg(feature = "unstable-msc4388")]
        if msc_4388 {
            grant.with_msc4388_support();
        }

        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login with a m.login.protocol message Alice
        // rejects.
        let rendezvous_server_clone = rendezvous_server.clone();
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                behaviour,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        let error = grant.await.expect_err("Alice should abort the login");
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");

        error
    }

    async fn test_grant_login_with_generated_qr_code_unsupported_protocol(msc_4388: bool) {
        let error = grant_login_with_generated_qr_code_rejected_protocol(
            BobBehaviour::UnsupportedProtocol,
            msc_4388,
        )
        .await;
        assert_let!(
            QRCodeGrantLoginError::UnsupportedProtocol(protocol) = error,
            "Alice should abort the login with expected error variant"
        );
        assert_eq!(protocol.as_str(), "m.unknown_protocol");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_unsupported_protocol_msc_4108() {
        test_grant_login_with_generated_qr_code_unsupported_protocol(false).await;
    }

    #[async_test]
    #[cfg(feature = "unstable-msc4388")]
    async fn test_grant_login_with_generated_qr_code_unsupported_protocol_msc_4388() {
        test_grant_login_with_generated_qr_code_unsupported_protocol(true).await;
    }

    async fn test_grant_login_with_generated_qr_code_unsupported_protocol_with_grant(
        msc_4388: bool,
    ) {
        let error = grant_login_with_generated_qr_code_rejected_protocol(
            BobBehaviour::UnsupportedProtocolWithDeviceAuthorizationGrant,
            msc_4388,
        )
        .await;
        assert_let!(
            QRCodeGrantLoginError::UnsupportedProtocol(protocol) = error,
            "Alice should abort the login with expected error variant"
        );
        assert_eq!(protocol.as_str(), "m.unknown_protocol");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_unsupported_protocol_with_grant_msc_4108() {
        test_grant_login_with_generated_qr_code_unsupported_protocol_with_grant(false).await;
    }

    #[async_test]
    #[cfg(feature = "unstable-msc4388")]
    async fn test_grant_login_with_generated_qr_code_unsupported_protocol_with_grant_msc_4388() {
        test_grant_login_with_generated_qr_code_unsupported_protocol_with_grant(true).await;
    }

    async fn test_grant_login_with_generated_qr_code_missing_device_authorization_grant(
        msc_4388: bool,
    ) {
        let error = grant_login_with_generated_qr_code_rejected_protocol(
            BobBehaviour::MissingDeviceAuthorizationGrant,
            msc_4388,
        )
        .await;
        assert_matches!(
            error,
            QRCodeGrantLoginError::SecureChannel(SecureChannelError::MessageDecode(
                MessageDecodeError::Json(_)
            )),
            "Alice should abort the login with expected error variant"
        );
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_missing_device_authorization_grant_msc_4108() {
        test_grant_login_with_generated_qr_code_missing_device_authorization_grant(false).await;
    }

    #[async_test]
    #[cfg(feature = "unstable-msc4388")]
    async fn test_grant_login_with_generated_qr_code_missing_device_authorization_grant_msc_4388() {
        test_grant_login_with_generated_qr_code_missing_device_authorization_grant(true).await;
    }

    async fn test_grant_login_with_generated_qr_code_mismatched_device_authorization_grant_layout(
        msc_4388: bool,
    ) {
        let error = grant_login_with_generated_qr_code_rejected_protocol(
            BobBehaviour::MismatchedDeviceAuthorizationGrantLayout,
            msc_4388,
        )
        .await;
        assert_let!(
            QRCodeGrantLoginError::UnexpectedMessage { expected, received } = error,
            "Alice should abort the login with expected error variant"
        );
        assert_eq!(expected, "m.login.protocol");
        assert_let!(QrAuthMessage::LoginProtocol { protocol, .. } = *received);
        // The layout of the other channel variant is rejected.
        if msc_4388 {
            assert_matches!(protocol, LoginProtocolData::Msc4108DeviceAuthorizationGrant(_));
        } else {
            assert_matches!(protocol, LoginProtocolData::Msc4388DeviceAuthorizationGrant(_));
        }
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_mismatched_device_authorization_grant_layout_msc_4108()
     {
        test_grant_login_with_generated_qr_code_mismatched_device_authorization_grant_layout(false)
            .await;
    }

    #[async_test]
    #[cfg(feature = "unstable-msc4388")]
    async fn test_grant_login_with_generated_qr_code_mismatched_device_authorization_grant_layout_msc_4388()
     {
        test_grant_login_with_generated_qr_code_mismatched_device_authorization_grant_layout(true)
            .await;
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_device_already_exists() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::DeviceAlreadyExists,
                qr_code_rx,
                checkcode_tx,
                Some(server),
                &rendezvous_server,
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::DeviceIDAlreadyInUse),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_device_already_exists() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::DeviceAlreadyExists,
                channel,
                checkcode_rx,
                Some(server),
                &rendezvous_server,
                alice.homeserver(),
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::DeviceIDAlreadyInUse),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_device_not_found() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrScanned(_)
                            )
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::DeviceNotCreated,
                qr_code_rx,
                checkcode_tx,
                Some(server),
                &rendezvous_server,
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::DeviceNotFound),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_device_not_found() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. })
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::DeviceNotCreated,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server,
                alice.homeserver(),
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::DeviceNotFound),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_session_expired() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = MockedRendezvousServer::new(
            server.server(),
            "abcdEFG12345",
            Duration::from_secs(2),
            false,
        )
        .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(_),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Bob does not scan the QR code and the channel is never connected.

        // Wait for the rendezvous session to time out.
        assert_matches!(grant.await, Err(QRCodeGrantLoginError::NotFound));
        updates_task.await.expect("Alice should run through all progress states");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_session_expired() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = MockedRendezvousServer::new(
            server.server(),
            "abcdEFG12345",
            Duration::from_secs(2),
            false,
        )
        .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Bob does not connect the channel.

        // Wait for the rendezvous session to time out.
        assert_matches!(grant.await, Err(QRCodeGrantLoginError::NotFound));
        updates_task.await.expect("Alice should run through all progress states");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_login_failure_instead_of_login_protocol() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let rendezvous_server_clone = rendezvous_server.clone();
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::LoginFailureInsteadOfLoginProtocol,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::LoginFailure { reason: LoginFailureReason::UserCancelled }),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_login_failure_instead_of_login_protocol() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::LoginFailureInsteadOfLoginProtocol,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server_clone,
                alice.homeserver(),
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::LoginFailure { reason: LoginFailureReason::UserCancelled }),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_login_failure_instead_of_login_success() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrScanned(_)
                            )
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::LoginFailureInsteadOfLoginSuccess,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::LoginFailure {
                reason: LoginFailureReason::AuthorizationExpired
            }),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_login_failure_instead_of_login_success() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. })
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::LoginFailureInsteadOfLoginSuccess,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server_clone,
                alice.homeserver(),
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::LoginFailure {
                reason: LoginFailureReason::AuthorizationExpired
            }),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_unexpected_message_instead_of_login_success() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrScanned(_)
                            )
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let rendezvous_server_clone = rendezvous_server.clone();
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::UnexpectedMessageInsteadOfLoginSuccess,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_let!(
            Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.success",
                received,
            }) = grant.await,
            "Alice should abort the login with expected error variant"
        );
        assert_matches!(
            *received,
            QrAuthMessage::LoginProtocolAccepted,
            "Alice should abort the login with expected error message"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_unexpected_message_instead_of_login_success() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. })
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        continuation_sender.confirm().await.expect("should be able to confirm");
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::UnexpectedMessageInsteadOfLoginSuccess,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server_clone,
                alice.homeserver(),
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_let!(
            Err(QRCodeGrantLoginError::UnexpectedMessage {
                expected: "m.login.success",
                received,
            }) = grant.await,
            "Alice should abort the login with expected error variant"
        );
        assert_matches!(
            *received,
            QrAuthMessage::LoginProtocolAccepted,
            "Alice should abort the login with expected error message"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_secure_channel_error() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let rendezvous_server_clone = rendezvous_server.clone();
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::InvalidJsonMessage,
                qr_code_rx,
                checkcode_tx,
                None,
                &rendezvous_server_clone,
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::SecureChannel(SecureChannelError::MessageDecode(
                MessageDecodeError::Json(_)
            ))),
            "Alice should abort the login with a SecureChannel error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_secure_channel_error() {
        let server = MatrixMockServer::new().await;
        let rendezvous_server = Arc::new(
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await,
        );
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process");
                    }
                }
                state = update;
            }
        });

        let rendezvous_server_clone = rendezvous_server.clone();
        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::InvalidJsonMessage,
                channel,
                checkcode_rx,
                None,
                &rendezvous_server_clone,
                alice.homeserver(),
                None,
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::SecureChannel(SecureChannelError::MessageDecode(
                MessageDecodeError::Json(_)
            ))),
            "Alice should abort the login with a SecureChannel error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_generated_qr_code_cancelled_while_waiting_for_auth() {
        let (protocol_accepted_tx, protocol_accepted_rx) = oneshot::channel();
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .generate();
        let (qr_code_tx, qr_code_rx) = oneshot::channel();
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut qr_code_tx = Some(qr_code_tx);
            let mut checkcode_rx = Some(checkcode_rx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrReady(qr_code_data),
                    ) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        qr_code_tx
                            .take()
                            .expect("The QR code should only be forwarded once")
                            .send(qr_code_data.clone())
                            .expect("Alice should be able to forward the QR code");
                    }
                    GrantLoginProgress::EstablishingSecureChannel(
                        GeneratedQrProgress::QrScanned(checkcode_sender),
                    ) => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrReady(_)
                            )
                        );
                        let checkcode = checkcode_rx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .await
                            .expect("Alice should receive the checkcode");
                        checkcode_sender
                            .send(checkcode)
                            .await
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(
                                GeneratedQrProgress::QrScanned(_)
                            )
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        // Wait for Bob to receive LoginProtocolAccepted.
                        protocol_accepted_rx
                            .await
                            .expect("Bob should signal that the protocol was accepted");
                        // The user cancels the login instead of confirming it.
                        continuation_sender.cancel().await.expect("should be able to cancel");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process after being cancelled");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_scanned_qr_code(
                BobBehaviour::CancelledWhileWaitingForAuth(protocol_accepted_tx),
                qr_code_rx,
                checkcode_tx,
                Some(server),
                &rendezvous_server,
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::LoginFailure { reason: LoginFailureReason::UserCancelled }),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }

    #[async_test]
    async fn test_grant_login_with_scanned_qr_code_cancelled_while_waiting_for_auth() {
        let (protocol_accepted_tx, protocol_accepted_rx) = oneshot::channel();
        let server = MatrixMockServer::new().await;
        let rendezvous_server =
            MockedRendezvousServer::new(server.server(), "abcdEFG12345", Duration::MAX, false)
                .await;
        debug!("Set up rendezvous server mock at {}", rendezvous_server.rendezvous_url);

        let device_authorization_grant = AuthorizationGrant {
            verification_uri_complete: Some(VerificationUriComplete::new(
                "https://id.matrix.org/device/abcde".to_owned(),
            )),
            verification_uri: EndUserVerificationUrl::new(
                "https://id.matrix.org/device/abcde?code=ABCDE".to_owned(),
            )
            .unwrap(),
        };

        server.mock_upload_keys().ok().expect(1).named("upload_keys").mount().await;
        server
            .mock_upload_cross_signing_keys()
            .ok()
            .expect(1)
            .named("upload_xsigning_keys")
            .mount()
            .await;
        server
            .mock_upload_cross_signing_signatures()
            .ok()
            .expect(1)
            .named("upload_xsigning_signatures")
            .mount()
            .await;

        // Create a secure channel on the new client (Bob) and extract the QR
        // code.
        let client = rendezvous_server.unlogged_client().await;
        let channel = SecureChannel::login(&client, false)
            .await
            .expect("Bob should be able to create a secure channel.");
        let qr_code_data = channel.qr_code_data().clone();

        // Create the existing client (Alice).
        let user_id = owned_user_id!("@alice:example.org");
        let device_id = owned_device_id!("ALICE_DEVICE");
        let alice = server
            .client_builder_for_crypto_end_to_end(&user_id, &device_id)
            .logged_in_with_oauth()
            .build()
            .await;
        alice
            .encryption()
            .bootstrap_cross_signing(None)
            .await
            .expect("Alice should be able to set up cross signing");

        // Prepare the login granting future using the QR code.
        let oauth = alice.oauth();
        let grant = oauth
            .grant_login_with_qr_code()
            .device_creation_timeout(Duration::from_secs(2))
            .scan(&qr_code_data);
        let (checkcode_tx, checkcode_rx) = oneshot::channel();

        // Spawn the updates task.
        let mut updates = grant.subscribe_to_progress();
        let mut state = grant.state.get();
        let verification_uri_complete =
            device_authorization_grant.clone().verification_uri_complete.unwrap().into_secret();
        assert_matches!(state.clone(), GrantLoginProgress::Starting);
        let updates_task = spawn(async move {
            let mut checkcode_tx = Some(checkcode_tx);

            while let Some(update) = updates.next().await {
                match &update {
                    GrantLoginProgress::Starting => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                    }
                    GrantLoginProgress::EstablishingSecureChannel(QrProgress { check_code }) => {
                        assert_matches!(state, GrantLoginProgress::Starting);
                        checkcode_tx
                            .take()
                            .expect("The checkcode should only be forwarded once")
                            .send(*check_code)
                            .expect("Alice should be able to forward the checkcode");
                    }
                    GrantLoginProgress::WaitingForAuth {
                        verification_uri,
                        continuation_sender,
                    } => {
                        assert_matches!(
                            state,
                            GrantLoginProgress::EstablishingSecureChannel(QrProgress { .. })
                        );
                        assert_eq!(verification_uri.as_str(), verification_uri_complete);
                        // Wait for Bob to receive LoginProtocolAccepted.
                        protocol_accepted_rx
                            .await
                            .expect("Bob should signal that the protocol was accepted");
                        // The user cancels the login instead of confirming it.
                        continuation_sender.cancel().await.expect("should be able to cancel");
                        break;
                    }
                    _ => {
                        panic!("Alice should abort the process after being cancelled");
                    }
                }
                state = update;
            }
        });

        // Let Bob request the login and run through the process.
        let bob_task = spawn(async move {
            request_login_with_generated_qr_code(
                BobBehaviour::CancelledWhileWaitingForAuth(protocol_accepted_tx),
                channel,
                checkcode_rx,
                Some(server),
                &rendezvous_server,
                alice.homeserver(),
                Some(device_authorization_grant),
                None,
            )
            .await;
        });

        // Wait for all tasks to finish / fail.
        assert_matches!(
            grant.await,
            Err(QRCodeGrantLoginError::LoginFailure { reason: LoginFailureReason::UserCancelled }),
            "Alice should abort the login with expected error"
        );
        updates_task.await.expect("Alice should run through all progress states");
        bob_task.await.expect("Bob's task should finish");
    }
}