Add Unit Tests for Animations.

src/Avalonia.Animation/AnimationInstance`1.cs

@@ -56,7 +56,7 @@ namespace Avalonia.Animation
 
             if (animation.IterationCount.RepeatType == IterationType.Many)
                 _iterationCount = animation.IterationCount.Value;
-                
+
             _animationDirection = animation.PlaybackDirection;
             _fillMode = animation.FillMode;
             _onCompleteAction = OnComplete;
@@ -174,11 +174,13 @@ namespace Avalonia.Animation
                 }
                 else if (playbackTime > iterDuration &
                          playbackTime <= iterationTime &
-                         iterDelay > 0 &
-                         // The last iteration's trailing delay should be skipped.
-                         (_currentIteration + 1) < _iterationCount)
+                         iterDelay > 0)
                 {
-                    DoDelay();
+                    // The last iteration's trailing delay should be skipped.
+                    if ((_currentIteration + 1) < _iterationCount)
+                        DoDelay();
+                    else
+                        DoComplete();
                 }
             }
         }

tests/Avalonia.Animation.UnitTests/AnimationIterationTests.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Avalonia.Animation;
+using Avalonia.Controls;
+using Avalonia.Styling;
+using Avalonia.UnitTests;
+using Avalonia.Data;
+using Xunit;
+
+namespace Avalonia.Animation.UnitTests
+{
+    public class AnimationIterationTests
+    {
+        [Fact]
+        public void Check_Initial_Inter_and_Trailing_Delay_Values()
+        {
+            var keyframe1 = new KeyFrame()
+            {
+                new Setter(Border.WidthProperty, 200d),
+            };
+
+            var keyframe2 = new KeyFrame()
+            {
+                new Setter(Border.WidthProperty, 100d),
+            };
+
+            keyframe1.Cue = new Cue(1d);
+            keyframe2.Cue = new Cue(0d);
+
+            var animation = new Animation()
+            {
+                Duration = TimeSpan.FromSeconds(3),
+                Delay = TimeSpan.FromSeconds(3),
+                DelayBetweenIterations = TimeSpan.FromSeconds(3),
+                IterationCount = new IterationCount(2),
+                Children =
+                {
+                    keyframe2,
+                    keyframe1
+                }
+            };
+
+            var border = new Border()
+            {
+                Height = 100d,
+                Width = 100d
+            };
+
+            var clock = new TestClock();
+            var animationRun = animation.RunAsync(border, clock);
+
+            clock.Step(TimeSpan.Zero);
+
+            // Initial Delay.
+            clock.Step(TimeSpan.FromSeconds(1));
+            Assert.Equal(border.Width, 0d);
+
+            clock.Step(TimeSpan.FromSeconds(6));
+
+            // First Inter-Iteration delay.
+            clock.Step(TimeSpan.FromSeconds(8));
+            Assert.Equal(border.Width, 200d);
+
+            // Trailing Delay should be non-existent.
+            clock.Step(TimeSpan.FromSeconds(14));
+            Assert.True(animationRun.Status == TaskStatus.RanToCompletion);
+            Assert.Equal(border.Width, 100d);
+        }
+    }
+}

tests/Avalonia.Animation.UnitTests/Avalonia.Animation.UnitTests.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
+  <PropertyGroup>
+    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <OutputType>Library</OutputType>
+  </PropertyGroup>
+  <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\Moq.props" />
+  <Import Project="..\..\build\XUnit.props" />
+  <Import Project="..\..\build\Rx.props" />
+  <Import Project="..\..\build\Microsoft.Reactive.Testing.props" />
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.Animation\Avalonia.Animation.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Base\Avalonia.Base.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Controls\Avalonia.Controls.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Input\Avalonia.Input.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Interactivity\Avalonia.Interactivity.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Layout\Avalonia.Layout.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Visuals\Avalonia.Visuals.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Styling\Avalonia.Styling.csproj" />
+    <ProjectReference Include="..\Avalonia.UnitTests\Avalonia.UnitTests.csproj" />
+  </ItemGroup>
+  <ItemGroup>
+    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
+  </ItemGroup>
+</Project>

tests/Avalonia.Animation.UnitTests/Properties/AssemblyInfo.cs

@@ -0,0 +1,10 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System.Reflection;
+using Xunit;
+
+[assembly: AssemblyTitle("Avalonia.Animation.UnitTests")]
+
+// Don't run tests in parallel.
+[assembly: CollectionBehavior(DisableTestParallelization = true)]

tests/Avalonia.Animation.UnitTests/TestClock.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+
+namespace Avalonia.Animation.UnitTests
+{
+    internal class TestClock : IClock, IDisposable
+    {
+        private IObserver<TimeSpan> _observer;
+
+        public PlayState PlayState { get; set; } = PlayState.Run;
+        
+        public void Dispose()
+        {
+            _observer?.OnCompleted();
+        }
+
+        public void Step(TimeSpan time)
+        {
+            _observer?.OnNext(time);
+        }
+
+        public IDisposable Subscribe(IObserver<TimeSpan> observer)
+        {
+            _observer = observer;
+            return this;
+        }
+    }
+}