add a unit test for gestures not being raised when parent handles event.

tests/Avalonia.Interactivity.UnitTests/GestureTests.cs

@@ -78,5 +78,36 @@ namespace Avalonia.Interactivity.UnitTests
 
             Assert.Equal(new[] { "bp", "dp", "br", "dr", "bt", "dt", "bp", "dp", "bdt", "ddt" }, result);
         }
+
+        [Fact]
+        public void DoubleTapped_Should_Not_Be_Rasied_if_Pressed_is_Handled()
+        {
+            Border border = new Border();
+            var decorator = new Decorator
+            {
+                Child = border
+            };
+            var result = new List<string>();
+
+            decorator.AddHandler(Border.PointerPressedEvent, (s, e) =>
+            {
+                result.Add("dp");
+                e.Handled = true;
+            });
+
+            decorator.AddHandler(Border.PointerReleasedEvent, (s, e) => result.Add("dr"));
+            decorator.AddHandler(Gestures.TappedEvent, (s, e) => result.Add("dt"));
+            decorator.AddHandler(Gestures.DoubleTappedEvent, (s, e) => result.Add("ddt"));
+            border.AddHandler(Border.PointerPressedEvent, (s, e) => result.Add("bp"));
+            border.AddHandler(Border.PointerReleasedEvent, (s, e) => result.Add("br"));
+            border.AddHandler(Gestures.TappedEvent, (s, e) => result.Add("bt"));
+            border.AddHandler(Gestures.DoubleTappedEvent, (s, e) => result.Add("bdt"));
+
+            border.RaiseEvent(new PointerPressedEventArgs());
+            border.RaiseEvent(new PointerReleasedEventArgs());
+            border.RaiseEvent(new PointerPressedEventArgs { ClickCount = 2 });
+
+            Assert.Equal(new[] { "bp", "dp", "br", "dr", "bt", "dt", "bp", "dp" }, result);
+        }
     }
 }