unit test for issue #2000 button with render transform don't trigger click

tests/Avalonia.Controls.UnitTests/ButtonTests.cs

@@ -1,7 +1,10 @@
 using System;
 using System.Windows.Input;
 using Avalonia.Data;
-using Avalonia.Markup.Data;
+using Avalonia.Input;
+using Avalonia.Media;
+using Avalonia.VisualTree;
+using Moq;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests
@@ -92,6 +95,164 @@ namespace Avalonia.Controls.UnitTests
             Assert.False(target.IsEnabled);
         }
 
+        [Fact]
+        public void Button_Is_Raising_Click()
+        {
+            var mouse = Mock.Of<IMouseDevice>();
+            IInputElement captured = null;
+            Mock.Get(mouse).Setup(m => m.GetPosition(It.IsAny<IVisual>())).Returns(new Point(50, 50));
+            Mock.Get(mouse).Setup(m => m.Capture(It.IsAny<IInputElement>())).Callback<IInputElement>(v => captured = v);
+            Mock.Get(mouse).Setup(m => m.Captured).Returns(() => captured);
+
+            var target = new TestButton() { Bounds = new Rect(0, 0, 100, 100) };
+
+            bool clicked = false;
+
+            target.Click += (s, e) => clicked = true;
+
+            RaisePointerEnter(target, mouse);
+            RaisePointerMove(target, mouse);
+            RaisePointerPressed(target, mouse, 1, MouseButton.Left);
+
+            Assert.Equal(captured, target);
+
+            RaisePointerReleased(target, mouse, MouseButton.Left);
+
+            Assert.Equal(captured, null);
+
+            Assert.True(clicked);
+        }
+
+        [Fact]
+        public void Button_Is_Not_Raising_Click_When_PointerReleased_Outside()
+        {
+            var mouse = Mock.Of<IMouseDevice>();
+            IInputElement captured = null;
+            Mock.Get(mouse).Setup(m => m.GetPosition(It.IsAny<IVisual>())).Returns(new Point(200, 50));
+            Mock.Get(mouse).Setup(m => m.Capture(It.IsAny<IInputElement>())).Callback<IInputElement>(v => captured = v);
+            Mock.Get(mouse).Setup(m => m.Captured).Returns(() => captured);
+
+            var target = new TestButton() { Bounds = new Rect(0, 0, 100, 100) };
+
+            bool clicked = false;
+
+            target.Click += (s, e) => clicked = true;
+
+            RaisePointerEnter(target, mouse);
+            RaisePointerMove(target, mouse);
+            RaisePointerPressed(target, mouse, 1, MouseButton.Left);
+            RaisePointerLeave(target, mouse);
+
+            Assert.Equal(captured, target);
+
+            RaisePointerReleased(target, mouse, MouseButton.Left);
+
+            Assert.Equal(captured, null);
+
+            Assert.False(clicked);
+        }
+
+        [Fact]
+        public void Button_With_RenderTransform_Is_Raising_Click()
+        {
+            var mouse = Mock.Of<IMouseDevice>();
+            IInputElement captured = null;
+            Mock.Get(mouse).Setup(m => m.GetPosition(It.IsAny<IVisual>())).Returns(new Point(150, 50));
+            Mock.Get(mouse).Setup(m => m.Capture(It.IsAny<IInputElement>())).Callback<IInputElement>(v => captured = v);
+            Mock.Get(mouse).Setup(m => m.Captured).Returns(() => captured);
+
+            var target = new TestButton()
+            {
+                Bounds = new Rect(0, 0, 100, 100),
+                RenderTransform = new TranslateTransform { X = 100, Y = 0 }
+            };
+
+            //actual bounds of button should  be 100,0,100,100 x -> translated 100 pixels
+            //so mouse with x=150 coordinates should trigger click
+            //button shouldn't count on bounds to calculate pointer is in the over or not, but
+            //on avalonia event system, as renderer hit test will properly calculate whether to send
+            //mouse over events to button based on rendered bounds
+            //note: button also may have not rectangular shape and only renderer hit testing is reliable
+
+            bool clicked = false;
+
+            target.Click += (s, e) => clicked = true;
+
+            RaisePointerEnter(target, mouse);
+            RaisePointerMove(target, mouse);
+            RaisePointerPressed(target, mouse, 1, MouseButton.Left);
+
+            Assert.Equal(captured, target);
+
+            RaisePointerReleased(target, mouse, MouseButton.Left);
+
+            Assert.Equal(captured, null);
+
+            Assert.True(clicked);
+        }
+
+        private class TestButton : Button
+        {
+            public new Rect Bounds
+            {
+                get => base.Bounds;
+                set => base.Bounds = value;
+            }
+        }
+
+        private void RaisePointerPressed(Button button, IMouseDevice device, int clickCount, MouseButton mouseButton)
+        {
+            button.RaiseEvent(new PointerPressedEventArgs
+            {
+                RoutedEvent = InputElement.PointerPressedEvent,
+                Source = button,
+                MouseButton = mouseButton,
+                ClickCount = clickCount,
+                Device = device,
+            });
+        }
+
+        private void RaisePointerReleased(Button button, IMouseDevice device, MouseButton mouseButton)
+        {
+            button.RaiseEvent(new PointerReleasedEventArgs
+            {
+                RoutedEvent = InputElement.PointerReleasedEvent,
+                Source = button,
+                MouseButton = mouseButton,
+                Device = device,
+            });
+        }
+
+        private void RaisePointerEnter(Button button, IMouseDevice device)
+        {
+            button.RaiseEvent(new PointerEventArgs
+            {
+                RoutedEvent = InputElement.PointerEnterEvent,
+                Source = button,
+                Device = device,
+            });
+        }
+
+        private void RaisePointerLeave(Button button, IMouseDevice device)
+        {
+            button.RaiseEvent(new PointerEventArgs
+            {
+                RoutedEvent = InputElement.PointerLeaveEvent,
+                Source = button,
+                Device = device,
+            });
+        }
+
+        private void RaisePointerMove(Button button, IMouseDevice device)
+        {
+            button.RaiseEvent(new PointerEventArgs
+            {
+                RoutedEvent = InputElement.PointerMovedEvent,
+                Source = button,
+                Device = device,
+            });
+        }
+
         private class TestCommand : ICommand
         {
             private bool _enabled;
@@ -123,4 +284,4 @@ namespace Avalonia.Controls.UnitTests
             }
         }
     }
-}
+}