Unit tests for the mixin changes

tests/Avalonia.Controls.UnitTests/Mixins/ContentControlMixinTests.cs

@@ -0,0 +1,136 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System.Collections.Generic;
+using Avalonia.Collections;
+using Avalonia.Controls.Mixins;
+using Avalonia.Controls.Presenters;
+using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Templates;
+using Avalonia.LogicalTree;
+using Moq;
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests.Mixins
+{
+    public class ContentControlMixinTests
+    {
+        [Fact]
+        public void Multiple_Mixin_Usages_Should_Not_Throw()
+        {
+            var target = new TestControl()
+            {
+                Template = new FuncControlTemplate(_ => new Panel
+                {
+                    Children =
+                    {
+                        new ContentPresenter { Name = "Content_1_Presenter" },
+                        new ContentPresenter { Name = "Content_2_Presenter" }
+                    }
+                })
+            };
+
+            var ex = Record.Exception(() => target.ApplyTemplate());
+
+            Assert.Null(ex);
+        }
+
+        [Fact]
+        public void Replacing_Template_Releases_Events()
+        {
+            var p1 = new ContentPresenter { Name = "Content_1_Presenter" };
+            var p2 = new ContentPresenter { Name = "Content_2_Presenter" };
+
+            var callIndex = -1;
+            var called = new bool[4];
+
+            void Callback()
+            {
+                if (callIndex >= 0)
+                    called[callIndex] = true;
+            }
+
+            var listMock = new Mock<IAvaloniaList<ILogical>>();
+            listMock.Setup(l => l.Contains(It.IsAny<ILogical>())).Returns(false).Callback(Callback);
+            var list = listMock.Object;
+
+            var target = new TestControl(list)
+            {
+                Template = new FuncControlTemplate(_ => new Panel
+                {
+                    Children =
+                    {
+                        p1,
+                        p2
+                    }
+                })
+            };
+            target.ApplyTemplate();
+
+            callIndex = 0;
+            p1.Content = new Control();
+            p1.UpdateChild();
+
+            callIndex = 1;
+            p2.Content = new Control();
+            p2.UpdateChild();
+
+            target.Template = null;
+
+            callIndex = 2;
+            p1.Content = new Control();
+            p1.UpdateChild();
+
+            callIndex = 3;
+            p2.Content = new Control();
+            p2.UpdateChild();
+
+
+            Assert.Equal(new[] { true, true, false, false }, called);
+        }
+
+        private class TestControl : TemplatedControl
+        {
+            public static readonly StyledProperty<object> Content1Property =
+                AvaloniaProperty.Register<TestControl, object>(nameof(Content1));
+
+            public static readonly StyledProperty<object> Content2Property =
+                AvaloniaProperty.Register<TestControl, object>(nameof(Content2));
+
+
+            static TestControl()
+            {
+                ContentControlMixin.Attach<TestControl>(Content1Property, x => x.GetLogicalChildren(), "Content_1_Presenter");
+                ContentControlMixin.Attach<TestControl>(Content2Property, x => x.GetLogicalChildren(), "Content_2_Presenter");
+            }
+
+            private IAvaloniaList<ILogical> _mock;
+
+            public TestControl()
+            {
+            }
+
+            public TestControl(IAvaloniaList<ILogical> mock)
+            {
+                _mock = mock;
+            }
+
+            public IAvaloniaList<ILogical> GetLogicalChildren()
+            {
+                return _mock ?? LogicalChildren;
+            }
+
+            public object Content1
+            {
+                get { return GetValue(Content1Property); }
+                set { SetValue(Content1Property, value); }
+            }
+
+            public object Content2
+            {
+                get { return GetValue(Content2Property); }
+                set { SetValue(Content2Property, value); }
+            }
+        }
+    }
+}