Add testing

tests/Avalonia.Markup.Xaml.UnitTests/Data/BindingTests_Method.cs

@@ -1,5 +1,4 @@
-using System.Reactive.Subjects;
-using System.Windows.Input;
+using System.ComponentModel;
 using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.UnitTests;
@@ -56,7 +55,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
                 Assert.Equal("Called 5", vm.Value);
             }
         }
-        
+
         [Fact]
         public void Binding_Method_To_TextBlock_Text_Works()
         {
@@ -79,6 +78,68 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             }
         }
 
+
+        [Theory]
+        [InlineData(null, "Not called")]
+        [InlineData("A", "Do A")]
+        public void Binding_Method_With_Parameter_To_Command_CanExecute(object commandParameter, string result)
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Button Name='button' Command='{Binding Do}' CommandParameter='{Binding Parameter, Mode=OneTime}'/>
+</Window>";
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+                var vm = new ViewModel()
+                {
+                    Parameter = commandParameter
+                };
+
+                button.DataContext = vm;
+                window.ApplyTemplate();
+
+                Assert.NotNull(button.Command);
+                PerformClick(button);
+                Assert.Equal(vm.Value, result);
+            }
+        }
+
+        [Fact]
+        public void Binding_Method_With_Parameter_To_Command_CanExecute_DependsOn()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
+    <Button Name='button' Command='{Binding Do}' CommandParameter='{Binding Parameter, Mode=OneWay}'/>
+</Window>";
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                var button = window.FindControl<Button>("button");
+                var vm = new ViewModel()
+                {
+                    Parameter = null,
+                };
+
+                button.DataContext = vm;
+                window.ApplyTemplate();
+
+                Assert.NotNull(button.Command);
+
+                Assert.Equal(button.IsEffectivelyEnabled, false);
+
+                vm.Parameter = true;
+                Threading.Dispatcher.UIThread.RunJobs();
+
+                Assert.Equal(button.IsEffectivelyEnabled, true);
+            }
+        }
+
         static void PerformClick(Button button)
         {
             button.RaiseEvent(new KeyEventArgs
@@ -88,12 +149,43 @@ namespace Avalonia.Markup.Xaml.UnitTests.Data
             });
         }
 
-        private class ViewModel
+        private class ViewModel : INotifyPropertyChanged
         {
+            public event PropertyChangedEventHandler PropertyChanged;
+
             public string Method() => Value = "Called";
             public string Method1(int i) => Value = $"Called {i}";
             public string Method2(int i, int j) => Value = $"Called {i},{j}";
             public string Value { get; private set; } = "Not called";
+
+            object _parameter;
+            public object Parameter
+            {
+                get
+                {
+                    return _parameter;
+                }
+                set
+                {
+                    if (_parameter == value)
+                    {
+                        return;
+                    }
+                    _parameter = value;
+                    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Parameter)));
+                }
+            }
+
+            public void Do(object parameter)
+            {
+                Value = $"Do {parameter}";
+            }
+
+            [Metadata.DependsOn(nameof(Parameter))]
+            public bool CanDo(object parameter)
+            {
+                return ReferenceEquals(null, parameter) == false;
+            }
         }
     }
 }