Test unexpected response during login.

proto/src/server/client.rs

@@ -156,7 +156,6 @@ mod tests {
 
   // TODO: Tests for all login error conditions:
   //
-  // - unexpected response
   // - read error
   // - write error
   // - stream closed
@@ -203,6 +202,57 @@ mod tests {
     server_task.await.expect("joining server");
   }
 
+  #[tokio::test]
+  async fn login_unexpected_response() {
+    init();
+
+    let listener = TcpListener::bind("localhost:0").await.expect("binding");
+    let address = listener.local_addr().expect("getting local address");
+
+    let server_task = tokio::spawn(async move {
+      let (mut stream, _) = listener.accept().await.expect("accepting");
+      let (read_half, write_half) = stream.split();
+      let mut reader = FrameReader::new(read_half);
+      let mut writer = FrameWriter::new(write_half);
+
+      let frame = reader.read().await.expect("reading login request");
+      let request = frame.expect("unwrapping login request");
+      assert!(is_login_request(&request));
+
+      writer
+        .write(&ServerResponse::UserStatusResponse(UserStatusResponse {
+          user_name: "shruti".to_string(),
+          status: UserStatus::Online,
+          is_privileged: false,
+        }))
+        .await
+        .expect("writing user status response");
+    });
+
+    let stream = TcpStream::connect(address).await.expect("connecting");
+
+    let err = Client::new(stream)
+      .login(credentials())
+      .await
+      .expect_err("logging in");
+
+    match err {
+      ClientLoginError::UnexpectedResponse(response) => {
+        assert_eq!(
+          response,
+          ServerResponse::UserStatusResponse(UserStatusResponse {
+            user_name: "shruti".to_string(),
+            status: UserStatus::Online,
+            is_privileged: false,
+          })
+        );
+      }
+      _ => panic!("wrong error: {:?}", err),
+    }
+
+    server_task.await.expect("joining server");
+  }
+
   #[tokio::test]
   async fn login_success() {
     init();