add test for style resources

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/StyleTests.cs

@@ -5,6 +5,7 @@ using System.Xml;
 using Avalonia.Controls;
 using Avalonia.Markup.Data;
 using Avalonia.Markup.Xaml.Styling;
+using Avalonia.Markup.Xaml.Templates;
 using Avalonia.Media;
 using Avalonia.Styling;
 using Avalonia.UnitTests;
@@ -38,6 +39,30 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             }
         }
 
+        [Fact]
+        public void DataTemplate_Can_Be_Added_To_Style_Resources()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformWrapper))
+            {
+                var xaml = @"
+<UserControl xmlns='https://github.com/avaloniaui'
+             xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
+    <UserControl.Styles>
+        <Style>
+            <Style.Resources>
+                <DataTemplate x:Key='dataTemplate'><TextBlock/></DataTemplate>
+            </Style.Resources>
+        </Style>
+    </UserControl.Styles>
+</UserControl>";
+                var loader = new AvaloniaXamlLoader();
+                var userControl = (UserControl)loader.Load(xaml);
+                var dataTemplate = (DataTemplate)((Style)userControl.Styles[0]).Resources["dataTemplate"];
+
+                Assert.NotNull(dataTemplate);
+            }
+        }
+
         [Fact]
         public void SolidColorBrush_Can_Be_Added_To_Style_Resources()
         {