Use NotifyingBase in unit tests.

And rename NotifyingBase.SubscriptionCount ->
PropertyChangedSubscriptionCount as we also track ErrorsChanged
subscription count.

tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_DataValidation.cs

@@ -10,6 +10,7 @@ using System.Reactive.Linq;
 using System.Runtime.CompilerServices;
 using Avalonia.Data;
 using Avalonia.Markup.Data;
+using Avalonia.UnitTests;
 using Xunit;
 
 namespace Avalonia.Markup.UnitTests.Data
@@ -54,7 +55,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
             observer.Subscribe(_ => { });
 
-            Assert.Equal(0, data.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -64,9 +65,9 @@ namespace Avalonia.Markup.UnitTests.Data
             var observer = new ExpressionObserver(data, nameof(data.MustBePositive), true);
             var sub = observer.Subscribe(_ => { });
 
-            Assert.Equal(1, data.SubscriptionCount);
+            Assert.Equal(1, data.PropertyChangedSubscriptionCount);
             sub.Dispose();
-            Assert.Equal(0, data.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -105,7 +106,7 @@ namespace Avalonia.Markup.UnitTests.Data
             }, result);
         }
 
-        public class ExceptionTest : INotifyPropertyChanged
+        public class ExceptionTest : NotifyingBase
         {
             private int _mustBePositive;
 
@@ -118,19 +119,14 @@ namespace Avalonia.Markup.UnitTests.Data
                     {
                         throw new ArgumentOutOfRangeException(nameof(value));
                     }
+
                     _mustBePositive = value;
+                    RaisePropertyChanged();
                 }
             }
-
-            public event PropertyChangedEventHandler PropertyChanged;
-
-            private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
-            {
-                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-            }
         }
 
-        private class IndeiTest : INotifyDataErrorInfo, INotifyPropertyChanged
+        private class IndeiTest : NotifyingBase, INotifyDataErrorInfo
         {
             private int _mustBePositive;
             private Dictionary<string, IList<string>> _errors = new Dictionary<string, IList<string>>();
@@ -142,7 +138,7 @@ namespace Avalonia.Markup.UnitTests.Data
                 set
                 {
                     _mustBePositive = value;
-                    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(MustBePositive)));
+                    RaisePropertyChanged();
 
                     if (value >= 0)
                     {
@@ -159,24 +155,14 @@ namespace Avalonia.Markup.UnitTests.Data
 
             public bool HasErrors => _mustBePositive >= 0;
 
-            public int SubscriptionCount { get; private set; }
+            public int ErrorsChangedSubscriptionCount { get; private set; }
 
             public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged
             {
-                add
-                {
-                    _errorsChanged += value;
-                    ++SubscriptionCount;
-                }
-                remove
-                {
-                    _errorsChanged -= value;
-                    --SubscriptionCount;
-                }
+                add { _errorsChanged += value; ++ErrorsChangedSubscriptionCount; }
+                remove { _errorsChanged -= value; --ErrorsChangedSubscriptionCount; }
             }
 
-            public event PropertyChangedEventHandler PropertyChanged;
-
             public IEnumerable GetErrors(string propertyName)
             {
                 IList<string> result;

tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Indexer.cs

@@ -189,7 +189,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
             var expected = new[] { "bar", "bar2" };
             Assert.Equal(expected, result);
-            Assert.Equal(0, data.Foo.SubscriptionCount);
+            Assert.Equal(0, data.Foo.PropertyChangedSubscriptionCount);
         }
 
         [Fact]

tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Observable.cs

@@ -47,7 +47,7 @@ namespace Avalonia.Markup.UnitTests.Data
                 Assert.Equal(new[] { AvaloniaProperty.UnsetValue, "foo" }, result);
 
                 sub.Dispose();
-                Assert.Equal(0, data.SubscriptionCount);
+                Assert.Equal(0, data.PropertyChangedSubscriptionCount);
             }
         }
 

tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Property.cs

@@ -111,7 +111,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
             sub.Dispose();
 
-            Assert.Equal(0, data.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -139,7 +139,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
             sub.Dispose();
 
-            Assert.Equal(0, data.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -156,8 +156,8 @@ namespace Avalonia.Markup.UnitTests.Data
 
             sub.Dispose();
 
-            Assert.Equal(0, data.SubscriptionCount);
-            Assert.Equal(0, data.Next.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, data.Next.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -175,9 +175,9 @@ namespace Avalonia.Markup.UnitTests.Data
 
             sub.Dispose();
 
-            Assert.Equal(0, data.SubscriptionCount);
-            Assert.Equal(0, data.Next.SubscriptionCount);
-            Assert.Equal(0, old.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, data.Next.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, old.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -196,9 +196,9 @@ namespace Avalonia.Markup.UnitTests.Data
 
             sub.Dispose();
 
-            Assert.Equal(0, data.SubscriptionCount);
-            Assert.Equal(0, data.Next.SubscriptionCount);
-            Assert.Equal(0, old.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, data.Next.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, old.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -221,10 +221,10 @@ namespace Avalonia.Markup.UnitTests.Data
 
             sub.Dispose();
 
-            Assert.Equal(0, data.SubscriptionCount);
-            Assert.Equal(0, data.Next.SubscriptionCount);
-            Assert.Equal(0, breaking.SubscriptionCount);
-            Assert.Equal(0, old.SubscriptionCount);
+            Assert.Equal(0, data.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, data.Next.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, breaking.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, old.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -327,8 +327,8 @@ namespace Avalonia.Markup.UnitTests.Data
 
             Assert.Equal(new[] { "foo", "bar", AvaloniaProperty.UnsetValue }, result);
 
-            Assert.Equal(0, first.SubscriptionCount);
-            Assert.Equal(0, second.SubscriptionCount);
+            Assert.Equal(0, first.PropertyChangedSubscriptionCount);
+            Assert.Equal(0, second.PropertyChangedSubscriptionCount);
         }
 
         [Fact]
@@ -351,7 +351,7 @@ namespace Avalonia.Markup.UnitTests.Data
 
         private interface INext
         {
-            int SubscriptionCount { get; }
+            int PropertyChangedSubscriptionCount { get; }
         }
 
         private class Class1 : NotifyingBase

tests/Avalonia.Markup.UnitTests/Data/IndeiValidatorTests.cs

@@ -8,6 +8,7 @@ using System.ComponentModel;
 using System.Runtime.CompilerServices;
 using Avalonia.Data;
 using Avalonia.Markup.Data.Plugins;
+using Avalonia.UnitTests;
 using Xunit;
 
 namespace Avalonia.Markup.UnitTests.Data
@@ -77,14 +78,14 @@ namespace Avalonia.Markup.UnitTests.Data
                 }, results);
         }
 
-        public class Data : INotifyPropertyChanged, INotifyDataErrorInfo
+        public class Data : NotifyingBase, INotifyDataErrorInfo
         {
             private int nonValidated;
 
             public int NonValidated
             {
                 get { return nonValidated; }
-                set { nonValidated = value; NotifyPropertyChanged(); }
+                set { nonValidated = value; RaisePropertyChanged(); }
             }
 
             private int mustBePositive;
@@ -92,29 +93,13 @@ namespace Avalonia.Markup.UnitTests.Data
             public int MustBePositive
             {
                 get { return mustBePositive; }
-                set
-                {
-                    mustBePositive = value;
-                    NotifyErrorsChanged();
-                }
+                set { mustBePositive = value; RaisePropertyChanged(); }
             }
 
-            public bool HasErrors
-            {
-                get
-                {
-                    return MustBePositive > 0;
-                }
-            }
+            public bool HasErrors => MustBePositive > 0;
 
-            public event PropertyChangedEventHandler PropertyChanged;
             public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;
 
-            private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
-            {
-                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-            }
-
             private void NotifyErrorsChanged([CallerMemberName] string propertyName = "")
             {
                 ErrorsChanged?.Invoke(this, new DataErrorsChangedEventArgs(propertyName));

tests/Avalonia.Markup.UnitTests/Data/Plugins/ExceptionValidationPluginTests.cs

@@ -3,11 +3,10 @@
 
 using System;
 using System.Collections.Generic;
-using System.ComponentModel;
 using System.Reactive.Linq;
-using System.Runtime.CompilerServices;
 using Avalonia.Data;
 using Avalonia.Markup.Data.Plugins;
+using Avalonia.UnitTests;
 using Xunit;
 
 namespace Avalonia.Markup.UnitTests.Data.Plugins
@@ -38,7 +37,7 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
             }, result);
         }
 
-        public class Data : INotifyPropertyChanged
+        public class Data : NotifyingBase
         {
             private int _mustBePositive;
 
@@ -55,17 +54,10 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
                     if (value != _mustBePositive)
                     {
                         _mustBePositive = value;
-                        NotifyPropertyChanged();
+                        RaisePropertyChanged();
                     }
                 }
             }
-
-            public event PropertyChangedEventHandler PropertyChanged;
-
-            private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
-            {
-                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-            }
         }
     }
 }

tests/Avalonia.Markup.UnitTests/Data/Plugins/IndeiValidationPluginTests.cs

@@ -8,6 +8,7 @@ using System.ComponentModel;
 using System.Reactive.Linq;
 using Avalonia.Data;
 using Avalonia.Markup.Data.Plugins;
+using Avalonia.UnitTests;
 using Xunit;
 
 namespace Avalonia.Markup.UnitTests.Data.Plugins
@@ -65,7 +66,7 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
             Assert.Equal(0, data.SubscriptionCount);
         }
 
-        public class Data : INotifyDataErrorInfo, INotifyPropertyChanged
+        public class Data : NotifyingBase, INotifyDataErrorInfo
         {
             private int _value;
             private int _maximum;
@@ -81,7 +82,7 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
                 set
                 {
                     _value = value;
-                    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
+                    RaisePropertyChanged();
                     UpdateError();
                 }
             }
@@ -102,8 +103,6 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
                 remove { _errorsChanged -= value; --SubscriptionCount; }
             }
 
-            public event PropertyChangedEventHandler PropertyChanged;
-
             public IEnumerable GetErrors(string propertyName)
             {
                 if (propertyName == nameof(Value) && _error != null)

tests/Avalonia.UnitTests/NotifyingBase.cs

@@ -16,7 +16,7 @@ namespace Avalonia.UnitTests
             add
             {
                 _propertyChanged += value;
-                ++SubscriptionCount;
+                ++PropertyChangedSubscriptionCount;
             }
 
             remove
@@ -24,12 +24,12 @@ namespace Avalonia.UnitTests
                 if (_propertyChanged?.GetInvocationList().Contains(value) == true)
                 {
                     _propertyChanged -= value;
-                    --SubscriptionCount;
+                    --PropertyChangedSubscriptionCount;
                 }
             }
         }
 
-        public int SubscriptionCount
+        public int PropertyChangedSubscriptionCount
         {
             get;
             private set;