diff --git a/tests/Avalonia.Animation.UnitTests/AnimatableTests.cs b/tests/Avalonia.Animation.UnitTests/AnimatableTests.cs
index 784f40fe1f..7633a761a3 100644
--- a/tests/Avalonia.Animation.UnitTests/AnimatableTests.cs
+++ b/tests/Avalonia.Animation.UnitTests/AnimatableTests.cs
@@ -113,7 +113,7 @@ namespace Avalonia.Animation.UnitTests
                 It.IsAny<IClock>(),
                 1.0,
                 0.5));
-            target.ResetCalls();
+            target.Invocations.Clear();
 
             control.SetValue(Visual.OpacityProperty, 0.8, BindingPriority.StyleTrigger);
 
@@ -135,7 +135,7 @@ namespace Avalonia.Animation.UnitTests
             target.Setup(x => x.Apply(control, It.IsAny<IClock>(), 1.0, 0.5)).Returns(sub.Object);
 
             control.Opacity = 0.5;
-            sub.ResetCalls();
+            sub.Invocations.Clear();
             control.Opacity = 0.4;
 
             sub.Verify(x => x.Dispose());
@@ -158,7 +158,7 @@ namespace Avalonia.Animation.UnitTests
             control.Opacity = 0.5;
 
             Assert.Equal(0.9, control.Opacity);
-            target.ResetCalls();
+            target.Invocations.Clear();
 
             control.Opacity = 0.4;
 
@@ -182,7 +182,7 @@ namespace Avalonia.Animation.UnitTests
                 It.IsAny<IClock>(),
                 1.0,
                 0.5));
-            target.ResetCalls();
+            target.Invocations.Clear();
 
             var root = (TestRoot)control.Parent;
             root.Child = null;
diff --git a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Metadata.cs b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Metadata.cs
index 161911dfd5..2edb3deff0 100644
--- a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Metadata.cs
+++ b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Metadata.cs
@@ -67,7 +67,7 @@ namespace Avalonia.Base.UnitTests
             public static readonly DirectProperty<Class1, string> DirectProperty =
                 AvaloniaProperty.RegisterDirect<Class1, string>("Styled", o => o.Direct, unsetValue: "foo");
 
-            private string _direct;
+            private string _direct = default;
 
             public string Direct
             {
@@ -92,7 +92,7 @@ namespace Avalonia.Base.UnitTests
             public static readonly DirectProperty<Class3, string> DirectProperty =
                 Class1.DirectProperty.AddOwner<Class3>(o => o.Direct, unsetValue: "baz");
 
-            private string _direct;
+            private string _direct = default;
 
             static Class3()
             {
diff --git a/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListExtenionsTests.cs b/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListExtenionsTests.cs
index 7f118a2c1d..b1b2d3d8f2 100644
--- a/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListExtenionsTests.cs
+++ b/tests/Avalonia.Base.UnitTests/Collections/AvaloniaListExtenionsTests.cs
@@ -6,10 +6,12 @@ namespace Avalonia.Base.UnitTests.Collections
 {
     public class AvaloniaListExtenionsTests
     {
+#pragma warning disable CS0618 // Type or member is obsolete
         [Fact]
         public void CreateDerivedList_Creates_Initial_Items()
         {
             var source = new AvaloniaList<int>(new[] { 0, 1, 2, 3 });
+
             var target = source.CreateDerivedList(x => new Wrapper(x));
             var result = target.Select(x => x.Value).ToList();
 
@@ -137,6 +139,8 @@ namespace Avalonia.Base.UnitTests.Collections
 
             Assert.Equal(source, result);
         }
+#pragma warning restore CS0618 // Type or member is obsolete
+
 
         private class Wrapper
         {
diff --git a/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs b/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs
index 1e1f4bd4b2..339cf8a334 100644
--- a/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs
+++ b/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs
@@ -356,7 +356,7 @@ namespace Avalonia.Base.UnitTests.Data.Core
         }
 
         [Fact]
-        public async Task Null_Value_Should_Use_TargetNullValue()
+        public void Null_Value_Should_Use_TargetNullValue()
         {
             var data = new Class1 { StringValue = "foo" };
 
diff --git a/tests/Avalonia.Base.UnitTests/Data/DefaultValueConverterTests.cs b/tests/Avalonia.Base.UnitTests/Data/DefaultValueConverterTests.cs
index efa81dcc1b..f522acf9ce 100644
--- a/tests/Avalonia.Base.UnitTests/Data/DefaultValueConverterTests.cs
+++ b/tests/Avalonia.Base.UnitTests/Data/DefaultValueConverterTests.cs
@@ -1,12 +1,11 @@
+using System;
+using System.ComponentModel;
 using System.Globalization;
-using Avalonia.Controls;
-using Avalonia.Data;
-using Xunit;
 using System.Windows.Input;
-using System;
+using Avalonia.Data;
 using Avalonia.Data.Converters;
 using Avalonia.Layout;
-using System.ComponentModel;
+using Xunit;
 
 namespace Avalonia.Base.UnitTests.Data.Converters
 {
@@ -251,6 +250,11 @@ namespace Avalonia.Base.UnitTests.Data.Converters
             {
                 return obj is CustomType other && this.Value == other.Value;
             }
+
+            public override int GetHashCode()
+            {
+                return 8399587^Value.GetHashCode();
+            }
         }
 
         private class CustomTypeConverter : TypeConverter
diff --git a/tests/Avalonia.Benchmarks/NullRenderer.cs b/tests/Avalonia.Benchmarks/NullRenderer.cs
index 9a756aaf0b..c1701b5d57 100644
--- a/tests/Avalonia.Benchmarks/NullRenderer.cs
+++ b/tests/Avalonia.Benchmarks/NullRenderer.cs
@@ -9,8 +9,9 @@ namespace Avalonia.Benchmarks
     {
         public bool DrawFps { get; set; }
         public bool DrawDirtyRects { get; set; }
+#pragma warning disable CS0067
         public event EventHandler<SceneInvalidatedEventArgs> SceneInvalidated;
-
+#pragma warning restore CS0067
         public void AddDirty(IVisual visual)
         {
         }
diff --git a/tests/Avalonia.Benchmarks/NullThreadingPlatform.cs b/tests/Avalonia.Benchmarks/NullThreadingPlatform.cs
index ba84b5afcc..bb469a6b33 100644
--- a/tests/Avalonia.Benchmarks/NullThreadingPlatform.cs
+++ b/tests/Avalonia.Benchmarks/NullThreadingPlatform.cs
@@ -23,6 +23,9 @@ namespace Avalonia.Benchmarks
 
         public bool CurrentThreadIsLoopThread => true;
 
+#pragma warning disable CS0067
         public event Action<DispatcherPriority?> Signaled;
+#pragma warning restore CS0067
+
     }
 }
diff --git a/tests/Avalonia.Controls.UnitTests/BorderTests.cs b/tests/Avalonia.Controls.UnitTests/BorderTests.cs
index 6e2599c9fd..ab33eaaff9 100644
--- a/tests/Avalonia.Controls.UnitTests/BorderTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/BorderTests.cs
@@ -54,7 +54,7 @@ namespace Avalonia.Controls.UnitTests
 
             var root = new TestRoot(target);
             var renderer = Mock.Get(root.Renderer);
-            renderer.ResetCalls();
+            renderer.Invocations.Clear();
 
             ((SolidColorBrush)target.Background).Color = Colors.Green;
 
diff --git a/tests/Avalonia.Controls.UnitTests/PanelTests.cs b/tests/Avalonia.Controls.UnitTests/PanelTests.cs
index 79ee6d1236..f189638c7d 100644
--- a/tests/Avalonia.Controls.UnitTests/PanelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/PanelTests.cs
@@ -127,7 +127,7 @@ namespace Avalonia.Controls.UnitTests
 
             var root = new TestRoot(target);
             var renderer = Mock.Get(root.Renderer);
-            renderer.ResetCalls();
+            renderer.Invocations.Clear();
 
             ((SolidColorBrush)target.Background).Color = Colors.Green;
 
diff --git a/tests/Avalonia.Controls.UnitTests/Platform/DefaultMenuInteractionHandlerTests.cs b/tests/Avalonia.Controls.UnitTests/Platform/DefaultMenuInteractionHandlerTests.cs
index 64f35049ce..1a11091b81 100644
--- a/tests/Avalonia.Controls.UnitTests/Platform/DefaultMenuInteractionHandlerTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Platform/DefaultMenuInteractionHandlerTests.cs
@@ -503,26 +503,26 @@ namespace Avalonia.Controls.UnitTests.Platform
                 target.PointerEnter(item, enter);
                 Assert.True(timer.ActionIsQueued);
                 Mock.Get(parentItem).VerifySet(x => x.SelectedItem = item);
-                Mock.Get(parentItem).ResetCalls();
+                Mock.Get(parentItem).Invocations.Clear();
 
                 // SubMenu shown after a delay.
                 timer.Pulse();
                 Mock.Get(item).Verify(x => x.Open());
                 Mock.Get(item).SetupGet(x => x.IsSubMenuOpen).Returns(true);
-                Mock.Get(item).ResetCalls();
+                Mock.Get(item).Invocations.Clear();
 
                 // Pointer briefly exits item, but submenu remains open.
                 target.PointerLeave(item, leave);
                 Mock.Get(item).Verify(x => x.Close(), Times.Never);
-                Mock.Get(item).ResetCalls();
+                Mock.Get(item).Invocations.Clear();
 
                 // Pointer enters child item; is selected.
                 enter.Source = childItem;
                 target.PointerEnter(childItem, enter);
                 Mock.Get(item).VerifySet(x => x.SelectedItem = childItem);
                 Mock.Get(parentItem).VerifySet(x => x.SelectedItem = item);
-                Mock.Get(item).ResetCalls();
-                Mock.Get(parentItem).ResetCalls();
+                Mock.Get(item).Invocations.Clear();
+                Mock.Get(parentItem).Invocations.Clear();
             }
 
             [Fact]
diff --git a/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs b/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs
index c0440ebc7b..c7aa583b6f 100644
--- a/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs
+++ b/tests/Avalonia.Controls.UnitTests/Presenters/ContentPresenterTests_Standalone.cs
@@ -212,7 +212,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
             var root = new TestRoot(target);
             var renderer = Mock.Get(root.Renderer);
-            renderer.ResetCalls();
+            renderer.Invocations.Clear();
 
             ((SolidColorBrush)target.Background).Color = Colors.Green;
 
diff --git a/tests/Avalonia.Controls.UnitTests/TextBlockTests.cs b/tests/Avalonia.Controls.UnitTests/TextBlockTests.cs
index 2d2c197220..b180a536a5 100644
--- a/tests/Avalonia.Controls.UnitTests/TextBlockTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TextBlockTests.cs
@@ -37,7 +37,7 @@ namespace Avalonia.Controls.UnitTests
 
             var root = new TestRoot(target);
             var renderer = Mock.Get(root.Renderer);
-            renderer.ResetCalls();
+            renderer.Invocations.Clear();
 
             ((SolidColorBrush)target.Background).Color = Colors.Green;
 
@@ -54,7 +54,7 @@ namespace Avalonia.Controls.UnitTests
 
             var root = new TestRoot(target);
             var renderer = Mock.Get(root.Renderer);
-            renderer.ResetCalls();
+            renderer.Invocations.Clear();
 
             ((SolidColorBrush)target.Foreground).Color = Colors.Green;
 
diff --git a/tests/Avalonia.DesignerSupport.TestApp/App.xaml.cs b/tests/Avalonia.DesignerSupport.TestApp/App.xaml.cs
index 653a51232b..97b6b9021a 100644
--- a/tests/Avalonia.DesignerSupport.TestApp/App.xaml.cs
+++ b/tests/Avalonia.DesignerSupport.TestApp/App.xaml.cs
@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
 
 namespace Avalonia.DesignerSupport.TestApp
@@ -13,5 +9,12 @@ namespace Avalonia.DesignerSupport.TestApp
         {
             AvaloniaXamlLoader.Load(this);
         }
+
+        public override void OnFrameworkInitializationCompleted()
+        {
+            if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+                desktop.MainWindow = new MainWindow();
+            base.OnFrameworkInitializationCompleted();
+        }
     }
 }
diff --git a/tests/Avalonia.DesignerSupport.TestApp/Program.cs b/tests/Avalonia.DesignerSupport.TestApp/Program.cs
index c7c60a4eca..b8428511b3 100644
--- a/tests/Avalonia.DesignerSupport.TestApp/Program.cs
+++ b/tests/Avalonia.DesignerSupport.TestApp/Program.cs
@@ -1,24 +1,14 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-using Avalonia.Controls;
-
-namespace Avalonia.DesignerSupport.TestApp
+namespace Avalonia.DesignerSupport.TestApp
 {
     static class Program
     {
         /// <summary>
         /// The main entry point for the application.
         /// </summary>
-        static void Main()
-        {
-            BuildAvaloniaApp().Start<MainWindow>();
-        }
+        public static int Main(string[] args)
+            => BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
 
-        private static AppBuilder BuildAvaloniaApp()
-        {
-            return AppBuilder.Configure<App>().UsePlatformDetect();
-        }
+        public static AppBuilder BuildAvaloniaApp()
+          => AppBuilder.Configure<App>().UsePlatformDetect();
     }
 }
diff --git a/tests/Avalonia.Layout.UnitTests/LayoutableTests.cs b/tests/Avalonia.Layout.UnitTests/LayoutableTests.cs
index 44a5af94b9..a8aa0bbf0e 100644
--- a/tests/Avalonia.Layout.UnitTests/LayoutableTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/LayoutableTests.cs
@@ -112,7 +112,7 @@ namespace Avalonia.Layout.UnitTests
 
             root.Measure(Size.Infinity);
             root.Arrange(new Rect(root.DesiredSize));
-            target.ResetCalls();
+            target.Invocations.Clear();
 
             control.InvalidateMeasure();
             control.InvalidateMeasure();
@@ -133,7 +133,7 @@ namespace Avalonia.Layout.UnitTests
 
             root.Measure(Size.Infinity);
             root.Arrange(new Rect(root.DesiredSize));
-            target.ResetCalls();
+            target.Invocations.Clear();
 
             control.InvalidateArrange();
             control.InvalidateArrange();
@@ -163,7 +163,7 @@ namespace Avalonia.Layout.UnitTests
             Assert.False(control.IsMeasureValid);
             Assert.True(root.IsMeasureValid);
 
-            target.ResetCalls();
+            target.Invocations.Clear();
 
             root.Child = control;
 
diff --git a/tests/Avalonia.Layout.UnitTests/LayoutableTests_EffectiveViewportChanged.cs b/tests/Avalonia.Layout.UnitTests/LayoutableTests_EffectiveViewportChanged.cs
index 504e3fa585..f1cec24516 100644
--- a/tests/Avalonia.Layout.UnitTests/LayoutableTests_EffectiveViewportChanged.cs
+++ b/tests/Avalonia.Layout.UnitTests/LayoutableTests_EffectiveViewportChanged.cs
@@ -15,7 +15,9 @@ namespace Avalonia.Layout.UnitTests
         [Fact]
         public async Task EffectiveViewportChanged_Not_Raised_When_Control_Added_To_Tree()
         {
+#pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
             await RunOnUIThread.Execute(async () =>
+#pragma warning restore CS1998 // Async method lacks 'await' operators and will run synchronously
             {
                 var root = CreateRoot();
                 var target = new Canvas();
diff --git a/tests/Avalonia.LeakTests/ControlTests.cs b/tests/Avalonia.LeakTests/ControlTests.cs
index 0c7b966f29..b03ae00cfe 100644
--- a/tests/Avalonia.LeakTests/ControlTests.cs
+++ b/tests/Avalonia.LeakTests/ControlTests.cs
@@ -460,7 +460,7 @@ namespace Avalonia.LeakTests
                 
                 AttachShowAndDetachContextMenu(window);
 
-                Mock.Get(window.PlatformImpl).ResetCalls();
+                Mock.Get(window.PlatformImpl).Invocations.Clear();
                 dotMemory.Check(memory =>
                     Assert.Equal(initialMenuCount, memory.GetObjects(where => where.Type.Is<ContextMenu>()).ObjectsCount));
                 dotMemory.Check(memory =>
@@ -505,7 +505,7 @@ namespace Avalonia.LeakTests
                 BuildAndShowContextMenu(window);
                 BuildAndShowContextMenu(window);
 
-                Mock.Get(window.PlatformImpl).ResetCalls();
+                Mock.Get(window.PlatformImpl).Invocations.Clear();
                 dotMemory.Check(memory =>
                     Assert.Equal(initialMenuCount, memory.GetObjects(where => where.Type.Is<ContextMenu>()).ObjectsCount));
                 dotMemory.Check(memory =>
@@ -601,8 +601,9 @@ namespace Avalonia.LeakTests
         {
             public bool DrawFps { get; set; }
             public bool DrawDirtyRects { get; set; }
+#pragma warning disable CS0067
             public event EventHandler<SceneInvalidatedEventArgs> SceneInvalidated;
-
+#pragma warning restore CS0067
             public void AddDirty(IVisual visual)
             {
             }
diff --git a/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_Negation.cs b/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_Negation.cs
index 0be3bbbb9f..0028502eeb 100644
--- a/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_Negation.cs
+++ b/tests/Avalonia.Markup.UnitTests/Parsers/ExpressionObserverBuilderTests_Negation.cs
@@ -168,10 +168,23 @@ namespace Avalonia.Markup.UnitTests.Parsers
 
         private class Test : INotifyDataErrorInfo
         {
+            private string _dataValidationError;
+
             public bool Foo { get; set; }
             public object Bar { get; set; }
 
-            public string DataValidationError { get; set; }
+            public string DataValidationError
+            {
+                get => _dataValidationError;
+                set
+                {
+                    if (value == _dataValidationError)
+                        return;
+                    _dataValidationError = value;
+                    ErrorsChanged?
+                        .Invoke(this, new DataErrorsChangedEventArgs(nameof(DataValidationError)));
+                }
+            }
             public bool HasErrors => !string.IsNullOrWhiteSpace(DataValidationError);
 
             public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;
diff --git a/tests/Avalonia.RenderTests/Media/BitmapTests.cs b/tests/Avalonia.RenderTests/Media/BitmapTests.cs
index d52539c371..b629304b77 100644
--- a/tests/Avalonia.RenderTests/Media/BitmapTests.cs
+++ b/tests/Avalonia.RenderTests/Media/BitmapTests.cs
@@ -102,7 +102,9 @@ namespace Avalonia.Direct2D1.RenderTests.Media
         [InlineData(PixelFormat.Bgra8888), InlineData(PixelFormat.Rgba8888)]
         public void WriteableBitmapShouldBeUsable(PixelFormat fmt)
         {
+#pragma warning disable CS0618 // Type or member is obsolete
             var writeableBitmap = new WriteableBitmap(new PixelSize(256, 256), new Vector(96, 96), fmt);
+#pragma warning restore CS0618 // Type or member is obsolete
 
             var data = new int[256 * 256];
             for (int y = 0; y < 256; y++)
diff --git a/tests/Avalonia.Styling.UnitTests/ResourceDictionaryTests.cs b/tests/Avalonia.Styling.UnitTests/ResourceDictionaryTests.cs
index 84b0d09b61..d91d1fab9e 100644
--- a/tests/Avalonia.Styling.UnitTests/ResourceDictionaryTests.cs
+++ b/tests/Avalonia.Styling.UnitTests/ResourceDictionaryTests.cs
@@ -108,7 +108,7 @@ namespace Avalonia.Styling.UnitTests
             var target = new ResourceDictionary { { "foo", "bar" } };
 
             ((IResourceProvider)target).AddOwner(host.Object);
-            host.ResetCalls();
+            host.Invocations.Clear();
             ((IResourceProvider)target).RemoveOwner(host.Object);
 
             host.Verify(x => x.NotifyHostedResourcesChanged(It.IsAny<ResourcesChangedEventArgs>()));
@@ -120,7 +120,7 @@ namespace Avalonia.Styling.UnitTests
             var host = new Mock<IResourceHost>();
             var target = new ResourceDictionary(host.Object);
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             target.Add("foo", "bar");
 
             host.Verify(x => x.NotifyHostedResourcesChanged(It.IsAny<ResourcesChangedEventArgs>()));
@@ -132,7 +132,7 @@ namespace Avalonia.Styling.UnitTests
             var host = new Mock<IResourceHost>();
             var target = new ResourceDictionary(host.Object);
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             target.MergedDictionaries.Add(new ResourceDictionary
             {
                 { "foo", "bar" },
@@ -149,7 +149,7 @@ namespace Avalonia.Styling.UnitTests
             var host = new Mock<IResourceHost>();
             var target = new ResourceDictionary(host.Object);
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             target.MergedDictionaries.Add(new ResourceDictionary());
 
             host.Verify(
@@ -169,7 +169,7 @@ namespace Avalonia.Styling.UnitTests
                 }
             };
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             target.MergedDictionaries.RemoveAt(0);
 
             host.Verify(
@@ -189,7 +189,7 @@ namespace Avalonia.Styling.UnitTests
                 }
             };
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             ((IResourceDictionary)target.MergedDictionaries[0]).Add("foo", "bar");
 
             host.Verify(
diff --git a/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs b/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs
index 8ae556cc6f..d011c16ebb 100644
--- a/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs
+++ b/tests/Avalonia.Styling.UnitTests/SelectorTests_Child.cs
@@ -1,12 +1,7 @@
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Reactive;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
-using Avalonia.Collections;
 using Avalonia.Controls;
-using Avalonia.Data;
 using Avalonia.LogicalTree;
 using Xunit;
 
@@ -85,76 +80,6 @@ namespace Avalonia.Styling.UnitTests
                 get => Parent;
                 set => ((ISetLogicalParent)this).SetParent(value);
             }
-
-            public void ClearValue(AvaloniaProperty property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void ClearValue<T>(AvaloniaProperty<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void AddInheritanceChild(IAvaloniaObject child)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void RemoveInheritanceChild(IAvaloniaObject child)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void InheritanceParentChanged<T>(StyledPropertyBase<T> property, IAvaloniaObject oldParent, IAvaloniaObject newParent)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void InheritedPropertyChanged<T>(AvaloniaProperty<T> property, Optional<T> oldValue, Optional<T> newValue)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void ClearValue<T>(StyledPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void ClearValue<T>(DirectPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public T GetValue<T>(StyledPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public T GetValue<T>(DirectPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void SetValue<T>(StyledPropertyBase<T> property, T value, BindingPriority priority = BindingPriority.LocalValue)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void SetValue<T>(DirectPropertyBase<T> property, T value)
-            {
-                throw new NotImplementedException();
-            }
-
-            public IDisposable Bind<T>(StyledPropertyBase<T> property, IObservable<BindingValue<T>> source, BindingPriority priority = BindingPriority.LocalValue)
-            {
-                throw new NotImplementedException();
-            }
-
-            public IDisposable Bind<T>(DirectPropertyBase<T> property, IObservable<BindingValue<T>> source)
-            {
-                throw new NotImplementedException();
-            }
         }
 
         public class TestLogical1 : TestLogical
diff --git a/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs b/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs
index 81485f0345..aacf2ce223 100644
--- a/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs
+++ b/tests/Avalonia.Styling.UnitTests/SelectorTests_Descendent.cs
@@ -1,11 +1,7 @@
-using System;
 using System.Linq;
-using System.Reactive;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
-using Avalonia.Collections;
 using Avalonia.Controls;
-using Avalonia.Data;
 using Avalonia.LogicalTree;
 using Xunit;
 
@@ -115,76 +111,6 @@ namespace Avalonia.Styling.UnitTests
                 get => Parent;
                 set => ((ISetLogicalParent)this).SetParent(value);
             }
-
-            public void ClearValue(AvaloniaProperty property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void ClearValue<T>(AvaloniaProperty<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void AddInheritanceChild(IAvaloniaObject child)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void RemoveInheritanceChild(IAvaloniaObject child)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void InheritanceParentChanged<T>(StyledPropertyBase<T> property, IAvaloniaObject oldParent, IAvaloniaObject newParent)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void InheritedPropertyChanged<T>(AvaloniaProperty<T> property, Optional<T> oldValue, Optional<T> newValue)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void ClearValue<T>(StyledPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void ClearValue<T>(DirectPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public T GetValue<T>(StyledPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public T GetValue<T>(DirectPropertyBase<T> property)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void SetValue<T>(StyledPropertyBase<T> property, T value, BindingPriority priority = BindingPriority.LocalValue)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void SetValue<T>(DirectPropertyBase<T> property, T value)
-            {
-                throw new NotImplementedException();
-            }
-
-            public IDisposable Bind<T>(StyledPropertyBase<T> property, IObservable<BindingValue<T>> source, BindingPriority priority = BindingPriority.LocalValue)
-            {
-                throw new NotImplementedException();
-            }
-
-            public IDisposable Bind<T>(DirectPropertyBase<T> property, IObservable<BindingValue<T>> source)
-            {
-                throw new NotImplementedException();
-            }
         }
 
         public class TestLogical1 : TestLogical
diff --git a/tests/Avalonia.Styling.UnitTests/StyleTests.cs b/tests/Avalonia.Styling.UnitTests/StyleTests.cs
index 3e2bd68cf0..df94887340 100644
--- a/tests/Avalonia.Styling.UnitTests/StyleTests.cs
+++ b/tests/Avalonia.Styling.UnitTests/StyleTests.cs
@@ -443,7 +443,7 @@ namespace Avalonia.Styling.UnitTests
             var resources = new Mock<IResourceDictionary>();
             target.Resources = resources.Object;
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             ((IResourceProvider)target).AddOwner(host.Object);
             resources.Verify(x => x.AddOwner(host.Object), Times.Once);
         }
diff --git a/tests/Avalonia.Styling.UnitTests/StylesTests.cs b/tests/Avalonia.Styling.UnitTests/StylesTests.cs
index 9d3704c91d..88ab124e01 100644
--- a/tests/Avalonia.Styling.UnitTests/StylesTests.cs
+++ b/tests/Avalonia.Styling.UnitTests/StylesTests.cs
@@ -15,7 +15,7 @@ namespace Avalonia.Styling.UnitTests
             var style = new Mock<IStyle>();
             var rp = style.As<IResourceProvider>();
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             target.Add(style.Object);
 
             rp.Verify(x => x.AddOwner(host.Object));
@@ -29,7 +29,7 @@ namespace Avalonia.Styling.UnitTests
             var style = new Mock<IStyle>();
             var rp = style.As<IResourceProvider>();
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             target.Add(style.Object);
             target.Remove(style.Object);
 
@@ -58,7 +58,7 @@ namespace Avalonia.Styling.UnitTests
             var resources = new Mock<IResourceDictionary>();
             target.Resources = resources.Object;
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             ((IResourceProvider)target).AddOwner(host.Object);
             resources.Verify(x => x.AddOwner(host.Object), Times.Once);
         }
@@ -87,7 +87,7 @@ namespace Avalonia.Styling.UnitTests
             var resourceProvider = style.As<IResourceProvider>();
             target.Add(style.Object);
 
-            host.ResetCalls();
+            host.Invocations.Clear();
             ((IResourceProvider)target).AddOwner(host.Object);
             resourceProvider.Verify(x => x.AddOwner(host.Object), Times.Once);
         }
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
index bfcc341eed..e58eea42d8 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests.cs
@@ -756,7 +756,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
         private void IgnoreFirstFrame(IRenderLoopTask task, Mock<ISceneBuilder> sceneBuilder)
         {
             RunFrame(task);
-            sceneBuilder.ResetCalls();
+            sceneBuilder.Invocations.Clear();
         }
 
         private void RunFrame(IRenderLoopTask task)
diff --git a/tests/Avalonia.Visuals.UnitTests/VisualTests.cs b/tests/Avalonia.Visuals.UnitTests/VisualTests.cs
index 97ad608346..447a68aa69 100644
--- a/tests/Avalonia.Visuals.UnitTests/VisualTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/VisualTests.cs
@@ -173,7 +173,7 @@ namespace Avalonia.Visuals.UnitTests
             };
 
             root.Child = child;
-            renderer.ResetCalls();
+            renderer.Invocations.Clear();
             root.Child = null;
 
             renderer.Verify(x => x.AddDirty(child));