Add UT

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

@@ -0,0 +1,29 @@
+using System.Linq;
+using Avalonia.Data;
+using Avalonia.Styling;
+using Avalonia.UnitTests;
+using Xunit;
+
+namespace Avalonia.Markup.Xaml.UnitTests
+{
+    public class SetterTests : XamlTestBase
+    {
+        [Fact]
+        public void Setter_Should_Work_Outside_Of_Style_With_SetterTargetType_Attribute()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformWrapper))
+            {
+                var xaml = @"
+<Animation xmlns='https://github.com/avaloniaui' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' x:SetterTargetType='Avalonia.Controls.Button'>
+    <KeyFrame>
+        <Setter Property='Content' Value='{Binding}'/>
+    </KeyFrame>
+</Animation>";
+                var animation = (Animation.Animation)AvaloniaRuntimeXamlLoader.Load(xaml);
+                var setter = (Setter)animation.Children[0].Setters[0];
+
+                Assert.IsType<Binding>(setter.Value);
+            }
+        }
+    }
+}