Fix failing test.

Added a `PullRequestChanged` signal to `IPullRequestSession` because the pull request model may be changed in-place and rxui filters out non-distinct entries in a `WhenAny`.

Author: Steven Kirk

src/GitHub.Exports.Reactive/Services/IPullRequestSession.cs

@@ -25,6 +25,16 @@ public interface IPullRequestSession
         /// </summary>
         IPullRequestModel PullRequest { get; }
 
+        /// <summary>
+        /// Gets an observable that indicates that<see cref="PullRequest"/> has been updated.
+        /// </summary>
+        /// <remarks>
+        /// This notification is different to listening for a PropertyChanged event because the
+        /// pull request model may be updated in-place which will not result in a PropertyChanged
+        /// notification.
+        /// </remarks>
+        IObservable<IPullRequestModel> PullRequestChanged { get; }
+
         /// <summary>
         /// Gets the local repository.
         /// </summary>

src/GitHub.InlineReviews/Services/PullRequestSession.cs

@@ -9,6 +9,7 @@
 using GitHub.Services;
 using ReactiveUI;
 using System.Threading;
+using System.Reactive.Subjects;
 
 namespace GitHub.InlineReviews.Services
 {
@@ -30,6 +31,7 @@ public class PullRequestSession : ReactiveObject, IPullRequestSession
         string mergeBase;
         IReadOnlyList<IPullRequestSessionFile> files;
         IPullRequestModel pullRequest;
+        Subject<IPullRequestModel> pullRequestChanged = new Subject<IPullRequestModel>();
 
         public PullRequestSession(
             IPullRequestSessionService service,
@@ -155,6 +157,8 @@ public async Task Update(IPullRequestModel pullRequest)
             {
                 await UpdateFile(file);
             }
+
+            pullRequestChanged.OnNext(pullRequest);
         }
 
         async Task AddComment(IPullRequestReviewCommentModel comment)
@@ -233,6 +237,9 @@ private set
             }
         }
 
+        /// <inheritdoc/>
+        public IObservable<IPullRequestModel> PullRequestChanged => pullRequestChanged;
+
         /// <inheritdoc/>
         public ILocalRepositoryModel LocalRepository { get; }
 

src/GitHub.InlineReviews/Services/PullRequestSessionManager.cs

@@ -109,8 +109,7 @@ public async Task<IPullRequestSessionFile> GetLiveFile(
                 dispose.Add(this.WhenAnyValue(x => x.CurrentSession)
                     .Skip(1)
                     .Subscribe(_ => UpdateLiveFile(result, true).Forget()));
-                dispose.Add(this.WhenAnyValue(x => x.CurrentSession.PullRequest)
-                    .Skip(1)
+                dispose.Add(this.WhenAnyObservable(x => x.CurrentSession.PullRequestChanged)
                     .Subscribe(_ => UpdateLiveFile(result, true).Forget()));
 
                 result.ToDispose = dispose;