Added test.

tests/Avalonia.Controls.UnitTests/ButtonTests.cs

@@ -2,6 +2,7 @@
 using System.Windows.Input;
 using Avalonia.Data;
 using Avalonia.Input;
+using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.Rendering;
@@ -271,6 +272,19 @@ namespace Avalonia.Controls.UnitTests
 
         [Fact]
         public void Button_Invokes_CanExecute_When_CommandParameter_Changed()
+        {
+            var target = new Button();
+            var raised = 0;
+
+            target.Click += (s, e) => ++raised;
+
+            target.RaiseEvent(new RoutedEventArgs(AccessKeyHandler.AccessKeyPressedEvent));
+
+            Assert.Equal(1, raised);
+        }
+
+        [Fact]
+        public void Raises_Click_When_AccessKey_Raised()
         {
             var command = new TestCommand(p => p is bool value && value);
             var target = new Button { Command = command };