Merge pull request #3746 from michael-hawker/tests-visualtree

Setup Unit Test Infrastructure for VisualTree related tests

Author: michael-hawker

Microsoft.Toolkit.Uwp.UI/Extensions/Tree/LogicalTree.cs

@@ -200,7 +200,8 @@ public static IEnumerable<T> FindChildren<T>(this FrameworkElement element)
         }
 
         /// <summary>
-        /// Finds the logical parent element with the given name or returns null.
+        /// Finds the logical parent element with the given name or returns null. Note: Parent may only be set when the control is added to the VisualTree.
+        /// <seealso href="https://docs.microsoft.com/uwp/api/windows.ui.xaml.frameworkelement.parent#remarks"/>
         /// </summary>
         /// <param name="element">Child element.</param>
         /// <param name="name">Name of the control to find.</param>
@@ -226,7 +227,8 @@ public static FrameworkElement FindParentByName(this FrameworkElement element, s
         }
 
         /// <summary>
-        /// Find first logical parent control of a specified type.
+        /// Find first logical parent control of a specified type. Note: Parent may only be set when the control is added to the VisualTree.
+        /// <seealso href="https://docs.microsoft.com/uwp/api/windows.ui.xaml.frameworkelement.parent#remarks"/>
         /// </summary>
         /// <typeparam name="T">Type to search for.</typeparam>
         /// <param name="element">Child element.</param>

Microsoft.Toolkit.Uwp.UI/Helpers/CompositionTargetHelper.cs

@@ -16,17 +16,20 @@ public static class CompositionTargetHelper
         /// <summary>
         /// Provides a method to execute code after the rendering pass is completed.
         /// <seealso href="https://github.com/microsoft/microsoft-ui-xaml/blob/c045cde57c5c754683d674634a0baccda34d58c4/dev/dll/SharedHelpers.cpp#L399"/>
+        /// <seealso href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/"/>
         /// </summary>
         /// <param name="action">Action to be executed after render pass</param>
+        /// <param name="options"><see cref="TaskCreationOptions"/> for how to handle async calls with <see cref="TaskCompletionSource{TResult}"/>.</param>
         /// <returns>Awaitable Task</returns>
-        public static Task<bool> ExecuteAfterCompositionRenderingAsync(Action action)
+        public static Task<bool> ExecuteAfterCompositionRenderingAsync(Action action, TaskCreationOptions? options = null)
         {
             if (action is null)
             {
                 ThrowArgumentNullException();
             }
 
-            var taskCompletionSource = new TaskCompletionSource<bool>();
+            var taskCompletionSource = options.HasValue ? new TaskCompletionSource<bool>(options.Value)
+                : new TaskCompletionSource<bool>();
 
             try
             {

UnitTests/UnitTests.UWP/Extensions/Test_LogicalTreeExtensions.cs

@@ -0,0 +1,66 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.Toolkit.Uwp.Extensions;
+using Microsoft.Toolkit.Uwp.UI.Extensions;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Markup;
+
+namespace UnitTests.Extensions
+{
+    [TestClass]
+    public class Test_LogicalTreeExtensions : VisualUITestBase
+    {
+        [TestCategory("LogicalTree")]
+        [TestMethod]
+        public async Task Test_LogicalTree_FindParent_Exists()
+        {
+            await App.DispatcherQueue.EnqueueAsync(async () =>
+            {
+                var treeRoot = XamlReader.Load(@"<Page
+    xmlns=""http://schemas.microsoft.com/winfx/2006/xaml/presentation""
+    xmlns:x=""http://schemas.microsoft.com/winfx/2006/xaml"">
+    <Grid>
+        <Grid> <!-- Target -->
+            <Border/>
+            <Border>
+                <TextBlock/> <!-- Starting Point -->
+            </Border>
+        </Grid>
+    </Grid>
+</Page>") as Page;
+
+                // Test Setup
+                Assert.IsNotNull(treeRoot, "XAML Failed to Load");
+
+                // Initialize Visual Tree
+                await SetTestContentAsync(treeRoot);
+
+                var outerGrid = treeRoot.Content as Grid;
+
+                Assert.IsNotNull(outerGrid, "Couldn't find Page content.");
+
+                var targetGrid = outerGrid.Children.FirstOrDefault() as Grid;
+                Assert.IsNotNull(targetGrid, "Couldn't find Target Grid");
+                Assert.AreEqual(2, targetGrid.Children.Count, "Grid doesn't have right number of children.");
+
+                var secondBorder = targetGrid.Children[1] as Border;
+                Assert.IsNotNull(secondBorder, "Border not found.");
+
+                var startingPoint = secondBorder.Child as FrameworkElement;
+                Assert.IsNotNull(startingPoint, "Could not find starting element.");
+
+                // Main Test
+                var grid = startingPoint.FindParent<Grid>();
+
+                Assert.IsNotNull(grid, "Expected to find Grid");
+                Assert.AreEqual(targetGrid, grid, "Grid didn't match expected.");
+            });
+        }
+    }
+}

UnitTests/UnitTests.UWP/UI/Controls/Test_TextToolbar_Localization.cs

@@ -79,7 +79,7 @@ public void Test_TextToolbar_Localization_Override()
         [TestMethod]
         public async Task Test_TextToolbar_Localization_Override_Fr()
         {
-            await CoreApplication.MainView.DispatcherQueue.EnqueueAsync(async () =>
+            await App.DispatcherQueue.EnqueueAsync(async () =>
             {
                 // Just double-check we've got the right environment setup in our tests.
                 CollectionAssert.AreEquivalent(new string[] { "en-US", "fr" }, ApplicationLanguages.ManifestLanguages.ToArray(), "Missing locales for test");

UnitTests/UnitTests.UWP/UnitTestApp.xaml.cs

@@ -3,11 +3,14 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-
+using UnitTests.Extensions;
 using Windows.ApplicationModel;
 using Windows.ApplicationModel.Activation;
+using Windows.ApplicationModel.Core;
+using Windows.System;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Media;
 using Windows.UI.Xaml.Navigation;
 
 namespace UnitTests
@@ -17,6 +20,31 @@ namespace UnitTests
     /// </summary>
     public partial class App : Application
     {
+        // Holder for test content to abstract Window.Current.Content
+        public static FrameworkElement ContentRoot
+        {
+            get
+            {
+                var rootFrame = Window.Current.Content as Frame;
+                return rootFrame.Content as FrameworkElement;
+            }
+
+            set
+            {
+                var rootFrame = Window.Current.Content as Frame;
+                rootFrame.Content = value;
+            }
+        }
+
+        // Abstract CoreApplication.MainView.DispatcherQueue
+        public static DispatcherQueue DispatcherQueue
+        {
+            get
+            {
+                return CoreApplication.MainView.DispatcherQueue;
+            }
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="App"/> class.
         /// Initializes the singleton application object.  This is the first line of authored code
@@ -50,7 +78,10 @@ protected override void OnLaunched(LaunchActivatedEventArgs e)
             if (rootFrame == null)
             {
                 // Create a Frame to act as the navigation context and navigate to the first page
-                rootFrame = new Frame();
+                rootFrame = new Frame()
+                {
+                    CacheSize = 0 // Prevent any test pages from being cached
+                };
 
                 rootFrame.NavigationFailed += OnNavigationFailed;
 

UnitTests/UnitTests.UWP/UnitTests.UWP.csproj

@@ -18,7 +18,7 @@
     <ProjectTypeGuids>{A5A43C5B-DE2A-4C0C-9213-0A381AF9435A};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
     <UnitTestPlatformVersion Condition="'$(UnitTestPlatformVersion)' == ''">$(VisualStudioVersion)</UnitTestPlatformVersion>
     <AppxPackageSigningEnabled>false</AppxPackageSigningEnabled>
-    <LangVersion>8.0</LangVersion>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
   <Target Name="Pack">
   </Target>
@@ -114,10 +114,10 @@
       <Version>6.2.10</Version>
     </PackageReference>
     <PackageReference Include="MSTest.TestAdapter">
-      <Version>2.1.0</Version>
+      <Version>2.1.2</Version>
     </PackageReference>
     <PackageReference Include="MSTest.TestFramework">
-      <Version>2.1.0</Version>
+      <Version>2.1.2</Version>
     </PackageReference>
     <PackageReference Include="Newtonsoft.Json">
       <Version>10.0.3</Version>
@@ -150,6 +150,7 @@
     <Compile Include="Extensions\Test_FontIconExtensionMarkupExtension.cs" />
     <Compile Include="Extensions\Test_EnumValuesExtension.cs" />
     <Compile Include="Extensions\Test_NullableBoolMarkupExtension.cs" />
+    <Compile Include="Extensions\Test_LogicalTreeExtensions.cs" />
     <Compile Include="Geometry\Test_CanvasPathGeometry.cs" />
     <Compile Include="Geometry\Test_RegexFactory.cs" />
     <Compile Include="Geometry\Test_Utils.cs" />
@@ -208,6 +209,7 @@
     <Compile Include="UnitTestApp.xaml.cs">
       <DependentUpon>UnitTestApp.xaml</DependentUpon>
     </Compile>
+    <Compile Include="VisualUITestBase.cs" />
   </ItemGroup>
   <ItemGroup>
     <ApplicationDefinition Include="UnitTestApp.xaml">

UnitTests/UnitTests.UWP/VisualUITestBase.cs

@@ -0,0 +1,77 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Toolkit.Uwp.Extensions;
+using Microsoft.Toolkit.Uwp.UI.Helpers;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Threading.Tasks;
+using Windows.UI.Xaml;
+
+namespace UnitTests
+{
+    /// <summary>
+    /// Base class to be used in API tests which require UI layout or rendering to occur first.
+    /// For more E2E scenarios or testing components for user interation, see integration test suite instead.
+    /// Use this class when an API needs direct access to test functions of the UI itself in more simplistic scenarios (i.e. visual tree helpers).
+    /// </summary>
+    public class VisualUITestBase
+    {
+        /// <summary>
+        /// Sets the content of the test app to a simple <see cref="FrameworkElement"/> to load into the visual tree.
+        /// Waits for that element to be loaded and rendered before returning.
+        /// </summary>
+        /// <param name="content">Content to set in test app.</param>
+        /// <returns>When UI is loaded.</returns>
+        protected Task SetTestContentAsync(FrameworkElement content)
+        {
+            return App.DispatcherQueue.EnqueueAsync(() =>
+            {
+                var taskCompletionSource = new TaskCompletionSource<bool>();
+
+                async void Callback(object sender, RoutedEventArgs args)
+                {
+                    content.Loaded -= Callback;
+
+                    // Wait for first Render pass
+                    await CompositionTargetHelper.ExecuteAfterCompositionRenderingAsync(() => { });
+
+                    taskCompletionSource.SetResult(true);
+                }
+
+                // Going to wait for our original content to unload
+                content.Loaded += Callback;
+
+                // Trigger that now
+                try
+                {
+                    App.ContentRoot = content;
+                }
+                catch (Exception e)
+                {
+                    taskCompletionSource.SetException(e);
+                }
+
+                return taskCompletionSource.Task;
+            });
+        }
+
+        [TestCleanup]
+        public async Task Cleanup()
+        {
+            var taskCompletionSource = new TaskCompletionSource<bool>();
+
+            await App.DispatcherQueue.EnqueueAsync(() =>
+            {
+                // Going to wait for our original content to unload
+                App.ContentRoot.Unloaded += (_, _) => taskCompletionSource.SetResult(true);
+
+                // Trigger that now
+                App.ContentRoot = null;
+            });
+
+            await taskCompletionSource.Task;
+        }
+    }
+}