public async Task CollectionChangedHandlerInvokedForConjAsync() { var loader = new AsyncLoader <int>(Seq.ListBased, eventContext: new RunInlineSynchronizationContext()); var listener = Substitute.For <CollectionChangedHandler <int> >(); loader.CollectionChanged += listener; await loader.ConjAsync(1, CancellationToken.None); // --- Perform --- listener.Received().Invoke(loader, Fluent.Match <IntChangesAlias>(changes => changes.Should().ContainSingle().Which.ShouldBeEquivalentTo(new ItemChange <int>(ChangeType.Added, 1)))); }