Fix failing tests.

Author: grokys

test/GitHub.InlineReviews.UnitTests/Services/PullRequestSessionTests.cs

@@ -143,10 +143,11 @@ public async Task IsFalseWhenReviewCancelled()
             {
                 var currentUser = CreateActor();
                 var review = CreateReview(author: currentUser, state: PullRequestReviewState.Pending);
+                var service = Substitute.For<IPullRequestSessionService>();
                 var pr = CreatePullRequest(review);
 
                 var target = new PullRequestSession(
-                    Substitute.For<IPullRequestSessionService>(),
+                    service,
                     currentUser,
                     pr,
                     Substitute.For<ILocalRepositoryModel>(),
@@ -155,6 +156,7 @@ public async Task IsFalseWhenReviewCancelled()
 
                 Assert.That(target.HasPendingReview, Is.True);
 
+                service.CancelPendingReview(null, null).ReturnsForAnyArgs(CreatePullRequest());
                 await target.CancelReview();
 
                 Assert.That(target.HasPendingReview, Is.False);
@@ -329,6 +331,8 @@ public async Task CallsServiceWithNodeId()
                 var service = Substitute.For<IPullRequestSessionService>();
                 var target = CreateTargetWithPendingReview(service);
 
+                service.CancelPendingReview(null, null).ReturnsForAnyArgs(CreatePullRequest());
+
                 await target.CancelReview();
 
                 await service.Received(1).CancelPendingReview(
@@ -342,6 +346,8 @@ public async Task RemovesReviewFromModel()
                 var service = Substitute.For<IPullRequestSessionService>();
                 var target = CreateTargetWithPendingReview(service);
 
+                service.CancelPendingReview(null, null).ReturnsForAnyArgs(CreatePullRequest());
+
                 await target.CancelReview();
 
                 Assert.IsEmpty(target.PullRequest.Reviews);