chore: Add test helpers

(cherry picked from commit d1f4148)

src/Uno.UI.RuntimeTests/Extensions/FrameworkElementExtensions.cs

@@ -15,5 +15,11 @@ internal static class FrameworkElementExtensions
 		/// </summary>
 		public static Rect GetOnScreenBounds(this FrameworkElement element)
 			=> element.TransformToVisual(null).TransformBounds(new Rect(0, 0, element.ActualWidth, element.ActualHeight));
+
+		/// <summary>
+		/// Get bounds of <paramref name="element"/> relative to <paramref name="relativeTo"/>.
+		/// </summary>
+		public static Rect GetRelativeBounds(this FrameworkElement element, FrameworkElement relativeTo)
+			=> element.TransformToVisual(relativeTo).TransformBounds(new Rect(0, 0, element.ActualWidth, element.ActualHeight));
 	}
 }

src/Uno.UI.RuntimeTests/Helpers/TestsResourceHelper.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Uno.Disposables;
+using Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml_Controls;
+
+namespace Uno.UI.RuntimeTests.Helpers
+{
+	internal static class TestsResourceHelper
+	{
+		private static TestsResources _testsResources;
+
+		/// <summary>
+		/// Get resource defined in TestsResources.xaml (templates, styles etc)
+		/// </summary>
+		public static T GetResource<T>(string resourceName)
+		{
+			_testsResources ??= new TestsResources();
+			return (T)_testsResources[resourceName];
+		}
+	}
+}