Added tests for existing RelativeSource modes.

src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj

@@ -32,6 +32,7 @@
         <Compile Include="AvaloniaXamlLoaderPortableXaml.cs" />
         <Compile Include="AvaloniaXamlLoader.cs" />
         <Compile Include="Converters\SetterValueTypeConverter.cs" />
+        <Compile Include="Data\XBinding.cs" />
         <Compile Include="MarkupExtensions\StyleIncludeExtension.cs" />
         <Compile Include="PortableXaml\AvaloniaXamlContext.cs" />
         <Compile Include="PortableXaml\XamlBinding.cs" />

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

@@ -0,0 +1,57 @@
+// 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.Reactive.Subjects;
+using Avalonia.Controls;
+using Avalonia.UnitTests;
+using Xunit;
+
+namespace Avalonia.Markup.Xaml.UnitTests.Xaml
+{
+    public class BindingTests_RelativeSource
+    {
+        [Fact]
+        public void Binding_To_DataContext_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Button Name='button' Content='{Binding Foo, RelativeSource={RelativeSource DataContext}}'/>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                button.DataContext = new { Foo = "foo" };
+                window.ApplyTemplate();
+
+                Assert.Equal("foo", button.Content);
+            }
+        }
+
+        [Fact]
+        public void Binding_To_Self_Works()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Button Name='button' Content='{Binding Name, RelativeSource={RelativeSource Self}}'/>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+
+                button.DataContext = new { Foo = "foo" };
+                window.ApplyTemplate();
+
+                Assert.Equal("button", button.Content);
+            }
+        }
+    }
+}