adds tests

src/Avalonia.Base/Input/GestureRecognizers/ScrollGestureRecognizer.cs

@@ -96,7 +96,7 @@ namespace Avalonia.Input.GestureRecognizers
         }
         
         // Pixels per second speed that is considered to be the stop of inertial scroll
-        private const double InertialScrollSpeedEnd = 0;
+        private const double InertialScrollSpeedEnd = 5;
         
         public void PointerMoved(PointerEventArgs e)
         {

tests/Avalonia.Base.UnitTests/Input/GesturesTests.cs

@@ -1,6 +1,8 @@
 using System.Collections.Generic;
 using Avalonia.Controls;
 using Avalonia.Input;
+using Avalonia.Input.GestureRecognizers;
+using Avalonia.Media;
 using Avalonia.UnitTests;
 using Xunit;
 
@@ -201,5 +203,101 @@ namespace Avalonia.Base.UnitTests.Input
             border.AddHandler(Gestures.TappedEvent, (s, e) => result.Add("bt"));
             border.AddHandler(Gestures.DoubleTappedEvent, (s, e) => result.Add("bdt"));
         }
+
+        [Fact]
+        public void Pinched_Should_Not_Be_Raised_For_Same_Pointer()
+        {
+            var touch = new TouchTestHelper();
+
+            Border border = new Border()
+            {
+                Width = 100,
+                Height = 100,
+                Background = new SolidColorBrush(Colors.Red)
+            };
+            border.GestureRecognizers.Add(new PinchGestureRecognizer());
+            var decorator = new Decorator
+            {
+                Child = border
+            };
+            var raised = false;
+
+            decorator.AddHandler(Gestures.PinchEvent, (s, e) => raised = true);
+
+            var firstPoint = new Point(5, 5);
+            var secondPoint = new Point(10, 10);
+
+            touch.Down(border, position: firstPoint);
+            touch.Down(border, position: secondPoint);
+            touch.Down(border, position: new Point(20, 20));
+
+            Assert.False(raised);
+        }
+
+        [Fact]
+        public void Pinched_Should_Be_Raised_For_Two_Pointers_Moving()
+        {
+            Border border = new Border()
+            {
+                Width = 100,
+                Height = 100,
+                Background = new SolidColorBrush(Colors.Red)
+            };
+            border.GestureRecognizers.Add(new PinchGestureRecognizer());
+            var decorator = new Decorator
+            {
+                Child = border
+            };
+            var raised = false;
+
+            decorator.AddHandler(Gestures.PinchEvent, (s, e) => raised = true);
+
+            var firstPoint = new Point(5, 5);
+            var secondPoint = new Point(10, 10);
+
+            var firstTouch = new TouchTestHelper();
+            var secondTouch = new TouchTestHelper();
+
+            firstTouch.Down(border, position: firstPoint);
+            secondTouch.Down(border, position: secondPoint);
+            secondTouch.Move(border, position: new Point(20, 20));
+
+            Assert.True(raised);
+        }
+
+        [Fact]
+        public void Scrolling_Should_Start_After_Start_Distance_Is_Exceded()
+        {
+            Border border = new Border()
+            {
+                Width = 100,
+                Height = 100,
+                Background = new SolidColorBrush(Colors.Red)
+            };
+            border.GestureRecognizers.Add(new ScrollGestureRecognizer()
+            {
+                CanHorizontallyScroll = true,
+                CanVerticallyScroll = true,
+                ScrollStartDistance = 50
+            });
+            var decorator = new Decorator
+            {
+                Child = border
+            };
+            var raised = false;
+
+            decorator.AddHandler(Gestures.ScrollGestureEvent, (s, e) => raised = true);
+
+            var firstTouch = new TouchTestHelper();
+
+            firstTouch.Down(border, position: new Point(5, 5));
+            firstTouch.Move(border, position: new Point(20, 20));
+
+            Assert.False(raised);
+
+            firstTouch.Move(border, position: new Point(70, 20));
+
+            Assert.True(raised);
+        }
     }
 }

tests/Avalonia.UnitTests/TouchTestHelper.cs

@@ -0,0 +1,53 @@
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.VisualTree;
+
+namespace Avalonia.UnitTests
+{
+    public class TouchTestHelper
+    {
+        private readonly Pointer _pointer = new Pointer(Pointer.GetNextFreeId(), PointerType.Touch, true);
+        private ulong _nextStamp = 1;
+        private ulong Timestamp() => _nextStamp++;
+        public IInputElement Captured => _pointer.Captured;
+
+        public void Down(Interactive target, Point position = default, KeyModifiers modifiers = default)
+        {
+            Down(target, target, position, modifiers);
+        }
+
+        public void Down(Interactive target, Interactive source, Point position = default, KeyModifiers modifiers = default)
+        {
+            _pointer.Capture((IInputElement)target);
+            source.RaiseEvent(new PointerPressedEventArgs(source, _pointer, (Visual)source, position, Timestamp(), PointerPointProperties.None,
+                modifiers));
+        }
+
+        public void Move(Interactive target, in Point position, KeyModifiers modifiers = default) => Move(target, target, position, modifiers);
+
+        public void Move(Interactive target, Interactive source, in Point position, KeyModifiers modifiers = default)
+        {
+            target.RaiseEvent(new PointerEventArgs(InputElement.PointerMovedEvent, source, _pointer, (Visual)target, position,
+                Timestamp(), PointerPointProperties.None, modifiers));
+        }
+
+        public void Up(Interactive target, Point position = default, KeyModifiers modifiers = default)
+            => Up(target, target, position, modifiers);
+
+        public void Up(Interactive target, Interactive source, Point position = default, KeyModifiers modifiers = default)
+        {
+            source.RaiseEvent(new PointerReleasedEventArgs(source, _pointer, (Visual)target, position, Timestamp(), PointerPointProperties.None,
+                modifiers, MouseButton.None));
+            _pointer.Capture(null);
+        }
+
+        public void Tap(Interactive target, Point position = default,  KeyModifiers modifiers = default)
+            => Tap(target, target, position, modifiers);
+
+        public void Tap(Interactive target, Interactive source, Point position = default, KeyModifiers modifiers = default)
+        {
+            Down(target, source, position, modifiers);
+            Up(target, source, position, modifiers);
+        }
+    }
+}