Merge branch 'master' into fixes/1435-comment-no-diff-lines

Author: grokys

src/GitHub.App/ViewModels/GitHubPane/NavigationViewModel.cs

@@ -25,8 +25,8 @@ public class NavigationViewModel : ViewModelBase, INavigationViewModel
         public NavigationViewModel()
         {
             history = new ReactiveList<IPanePageViewModel>();
-            history.BeforeItemsAdded.Subscribe(BeforeItemAdded);
-            history.CollectionChanged += CollectionChanged;
+            history.Changing.Subscribe(CollectionChanging);
+            history.Changed.Subscribe(CollectionChanged);
 
             var pos = this.WhenAnyValue(
                 x => x.Index,
@@ -107,7 +107,7 @@ public bool Forward()
         public void Clear()
         {
             Index = -1;
-            history.RemoveRange(0, history.Count);
+            history.Clear();
         }
 
         public int RemoveAll(IPanePageViewModel page)
@@ -139,27 +139,34 @@ void ItemRemoved(int removedIndex, IPanePageViewModel page)
             }
         }
 
-        void CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        void CollectionChanging(NotifyCollectionChangedEventArgs e)
         {
-            using (DelayChangeNotifications())
+            if (e.Action == NotifyCollectionChangedAction.Add)
             {
-                switch (e.Action)
+                foreach (IPanePageViewModel page in e.NewItems)
                 {
-                    case NotifyCollectionChangedAction.Add:
-                        break;
-
-                    case NotifyCollectionChangedAction.Remove:
-                        for (var i = 0; i < e.OldItems.Count; ++i)
-                        {
-                            ItemRemoved(e.OldStartingIndex + i, (IPanePageViewModel)e.OldItems[i]);
-                        }
-                        break;
-
-                    case NotifyCollectionChangedAction.Reset:
-                        throw new NotSupportedException();
+                    BeforeItemAdded(page);
+                }
+            }
+            else if (e.Action == NotifyCollectionChangedAction.Reset)
+            {
+                foreach (var page in history)
+                {
+                    page.Dispose();
+                }
+            }
+        }
 
-                    default:
-                        throw new NotImplementedException();
+        void CollectionChanged(NotifyCollectionChangedEventArgs e)
+        {
+            using (DelayChangeNotifications())
+            {
+                if (e.Action == NotifyCollectionChangedAction.Remove)
+                {
+                    for (var i = 0; i < e.OldItems.Count; ++i)
+                    {
+                        ItemRemoved(e.OldStartingIndex + i, (IPanePageViewModel)e.OldItems[i]);
+                    }
                 }
             }
         }

test/UnitTests/GitHub.App/ViewModels/GitHubPane/NavigationViewModelTests.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Reactive;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
@@ -309,6 +311,36 @@ public void CallsDeactivatedAndThenDisposedOnPages()
                 first.Dispose();
             });
         }
+
+        [Test]
+        public void DoesntThrowWhenHistoryHasMoreThan10Items()
+        {
+            var target = new NavigationViewModel();
+            var pages = new List<IPanePageViewModel>();
+
+            for (var i = 0; i < 11; ++i)
+            {
+                var page = CreatePage();
+                pages.Add(page);
+                target.NavigateTo(page);
+            }
+
+            foreach (var page in pages)
+            {
+                page.ClearReceivedCalls();
+            }
+
+            target.Clear();
+
+            pages.Last().Received().Deactivated();
+            pages.Last().Received().Dispose();
+
+            foreach (var page in pages.Take(pages.Count - 1))
+            {
+                page.DidNotReceive().Deactivated();
+                page.Received().Dispose();
+            }
+        }
     }
 
     public class TheRemoveMethod