Fix nullability warnings

Gui enhancements - Run selected on enter or double click

.gitignore

@@ -214,3 +214,4 @@ FakesAssemblies/
 **/*.Server/GeneratedArtifacts
 **/*.Server/ModelManifest.xml
 _Pvt_Extensions
+/Settings.XamlStyle

SampleTestAssembly/SampleTestAssembly.csproj

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props" Condition="Exists('..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props')" />
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -66,12 +65,6 @@
     <None Include="packages.config" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
-    <PropertyGroup>
-      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
-    </PropertyGroup>
-    <Error Condition="!Exists('..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props'))" />
-  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">

SampleTestAssembly/packages.config

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Microsoft.Net.Compilers" version="2.2.0" targetFramework="net452" developmentDependency="true" />
   <package id="xunit" version="2.1.0" targetFramework="net452" />
   <package id="xunit.abstractions" version="2.0.0" targetFramework="net452" />
   <package id="xunit.assert" version="2.1.0" targetFramework="net452" />

xunit.runner.data/ClientReader.cs

@@ -7,7 +7,7 @@ namespace Xunit.Runner.Data
     {
         private readonly BinaryReader _reader;
         private bool _closed;
-        private Exception _exception;
+        private Exception? _exception;
 
         public bool IsConnected => !_closed;
 

xunit.runner.data/xunit.runner.data.csproj

@@ -48,11 +48,6 @@
     <Compile Include="TestDataKind.cs" />
     <Compile Include="TestResultData.cs" />
   </ItemGroup>
-  <ItemGroup>
-    <PackageReference Include="Microsoft.Net.Compilers">
-      <Version>2.2.0</Version>
-    </PackageReference>
-  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

xunit.runner.worker/packages.config

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Microsoft.Net.Compilers" version="2.2.0" targetFramework="net46" developmentDependency="true" />
   <package id="xunit.abstractions" version="2.0.0" targetFramework="net452" />
   <package id="xunit.runner.utility" version="2.1.0" targetFramework="net46" />
 </packages>

xunit.runner.worker/xunit.runner.worker.csproj

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props" Condition="Exists('..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props')" />
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -77,12 +76,6 @@
     </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
-    <PropertyGroup>
-      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
-    </PropertyGroup>
-    <Error Condition="!Exists('..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props'))" />
-  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">

xunit.runner.wpf/CommandBindings.cs

@@ -16,16 +16,14 @@ namespace Xunit.Runner.Wpf
             }
         }
 
-        public static CommandBindingCollection GetRegistration(UIElement element)
+        public static CommandBindingCollection? GetRegistration(UIElement element)
             => (element != null ? (CommandBindingCollection)element.GetValue(Registration) : null);
 
         private static void OnRegistrationChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
         {
-            UIElement element = sender as UIElement;
-            if (element != null)
+            if (sender is UIElement element)
             {
-                CommandBindingCollection bindings = e.NewValue as CommandBindingCollection;
-                if (bindings != null)
+                if (e.NewValue is CommandBindingCollection bindings)
                 {
                     element.CommandBindings.AddRange(bindings);
                 }

xunit.runner.wpf/Converters/TestStateConverter.cs

@@ -33,7 +33,7 @@ namespace Xunit.Runner.Wpf.Converters
             return image;
         }
 
-        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        public object? Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
             var state = (TestState)value;
             if (targetType == typeof(Brush))

xunit.runner.wpf/FilteredCollectionView.cs

@@ -283,7 +283,13 @@ namespace Xunit.Runner.Wpf
 
         object IList.this[int index]
         {
-            get { return this[index]; }
+            get
+            {
+                // Can't figure out how to not get a warning here.
+#pragma warning disable CS8603
+                return this[index];
+#pragma warning restore
+            }
             set { throw new NotSupportedException(); }
         }
 

xunit.runner.wpf/Impl/RemoteTestUtil.BackgroundRunner.cs

@@ -55,13 +55,13 @@ namespace Xunit.Runner.Wpf.Impl
         /// <typeparam name="T"></typeparam>
         private sealed class BackgroundReader<T> where T : class
         {
-            private readonly ConcurrentQueue<T> _queue;
+            private readonly ConcurrentQueue<T?> _queue;
             private readonly ClientReader _reader;
             private readonly Func<ClientReader, T> _readValue;
 
             internal ClientReader Reader => _reader;
 
-            internal BackgroundReader(ConcurrentQueue<T> queue, ClientReader reader, Func<ClientReader, T> readValue)
+            internal BackgroundReader(ConcurrentQueue<T?> queue, ClientReader reader, Func<ClientReader, T> readValue)
             {
                 _queue = queue;
                 _reader = reader;
@@ -111,7 +111,7 @@ namespace Xunit.Runner.Wpf.Impl
             private const int MaxResultPerTick = 1000;
 
             private readonly Connection _connection;
-            private readonly ConcurrentQueue<T> _queue;
+            private readonly ConcurrentQueue<T?> _queue;
             private readonly DispatcherTimer _timer;
             private readonly Action<List<T>> _callback;
             private readonly int _maxPerTick;
@@ -122,7 +122,7 @@ namespace Xunit.Runner.Wpf.Impl
             internal BackgroundProducer(
                 Connection connection, 
                 Dispatcher dispatcher, 
-                ConcurrentQueue<T> queue,
+                ConcurrentQueue<T?> queue,
                 Action<List<T>> callback,
                 int maxResultPerTick = MaxResultPerTick,
                 TimeSpan? interval = null)
@@ -144,8 +144,7 @@ namespace Xunit.Runner.Wpf.Impl
                 var i = 0;
                 var list = new List<T>();
                 var isDone = false;
-                T value;
-                while (i < _maxPerTick && _queue.TryDequeue(out value))
+                while (i < _maxPerTick && _queue.TryDequeue(out T? value))
                 {
                     if (value == null)
                     {

xunit.runner.wpf/Impl/RemoteTestUtil.Connection.cs

@@ -8,10 +8,10 @@ namespace Xunit.Runner.Wpf.Impl
     {
         private sealed class Connection : IDisposable
         {
-            private NamedPipeClientStream _stream;
+            private NamedPipeClientStream? _stream;
             private ClientReader _reader;
 
-            internal NamedPipeClientStream Stream => _stream;
+            internal NamedPipeClientStream Stream => _stream ?? throw new ObjectDisposedException(nameof(Connection));
 
             internal ClientReader Reader => _reader;
 

xunit.runner.wpf/Impl/RemoteTestUtil.cs

@@ -123,7 +123,7 @@ namespace Xunit.Runner.Wpf.Impl
         private async Task ProcessResultsCore<T>(Connection connection, Func<ClientReader, T> readValue, Action<List<T>> callback, CancellationToken cancellationToken)
             where T : class
         {
-            var queue = new ConcurrentQueue<T>();
+            var queue = new ConcurrentQueue<T?>();
             var backgroundReader = new BackgroundReader<T>(queue, new ClientReader(connection.Stream), readValue);
             var backgroundProducer = new BackgroundProducer<T>(connection, _dispatcher, queue, callback);
 

xunit.runner.wpf/Impl/TestAssemblyWatcher.cs

@@ -14,7 +14,7 @@ namespace Xunit.Runner.Wpf.Impl
         private readonly IDictionary<string, FileSystemWatcher> watchedAssemblies = new Dictionary<string, FileSystemWatcher>();
         private readonly Dispatcher dispatcher;
         private bool isEnabled = false;
-        private ReloadDebouncer debouncer;
+        private ReloadDebouncer? debouncer;
 
         public TestAssemblyWatcher(Dispatcher dispatcher)
         {

xunit.runner.wpf/MainWindow.xaml

@@ -1,24 +1,25 @@
-<Window x:Class="Xunit.Runner.Wpf.MainWindow"
-        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-        xmlns:local="clr-namespace:Xunit.Runner.Wpf"
-        xmlns:converters="clr-namespace:Xunit.Runner.Wpf.Converters"
-        xmlns:vm="clr-namespace:Xunit.Runner.Wpf.ViewModel"
-        xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
-        xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Platform"
-        xmlns:sys="clr-namespace:System;assembly=mscorlib"
-        mc:Ignorable="d"
-        DataContext="{Binding Main, Source={StaticResource Locator}}"
-        Title="xUnit.net Test Runner"
-        Icon="Artwork\Application.ico"
-        ResizeMode="CanResizeWithGrip"
-        Height="600"
-        MinHeight="525"
-        Width="525"
-        MinWidth="425"
-        Name="Main">
+<Window
+    x:Class="Xunit.Runner.Wpf.MainWindow"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Platform"
+    xmlns:converters="clr-namespace:Xunit.Runner.Wpf.Converters"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
+    xmlns:local="clr-namespace:Xunit.Runner.Wpf"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:sys="clr-namespace:System;assembly=mscorlib"
+    xmlns:vm="clr-namespace:Xunit.Runner.Wpf.ViewModel"
+    Name="Main"
+    Title="xUnit.net Test Runner"
+    Width="525"
+    Height="600"
+    MinWidth="425"
+    MinHeight="525"
+    DataContext="{Binding Main, Source={StaticResource Locator}}"
+    Icon="Artwork\Application.ico"
+    ResizeMode="CanResizeWithGrip"
+    mc:Ignorable="d">
 
     <i:Interaction.Triggers>
         <i:EventTrigger EventName="Loaded">
@@ -43,12 +44,10 @@
 
         <Menu Grid.Row="0">
             <MenuItem Header="_File">
-                <MenuItem Header="E_xit"
-                          Command="{Binding ExitCommand}" />
+                <MenuItem Command="{Binding ExitCommand}" Header="E_xit" />
             </MenuItem>
             <MenuItem Header="_Assembly">
-                <MenuItem Header="_Open"
-                          Command="ApplicationCommands.Open" />
+                <MenuItem Command="ApplicationCommands.Open" Header="_Open" />
                 <MenuItem Header="R_ecent" ItemsSource="{Binding RecentAssemblies}">
                     <MenuItem.ItemContainerStyle>
                         <Style TargetType="MenuItem">
@@ -59,10 +58,14 @@
                     </MenuItem.ItemContainerStyle>
                 </MenuItem>
                 <Separator />
-                <MenuItem Header="_Unload" Command="{Binding AssemblyRemoveAllCommand}"/>
-                <MenuItem Header="_Reload" Command="{Binding AssemblyReloadAllCommand}" />
+                <MenuItem Command="{Binding AssemblyRemoveAllCommand}" Header="_Unload" />
+                <MenuItem Command="{Binding AssemblyReloadAllCommand}" Header="_Reload" />
                 <Separator />
-                <MenuItem Header="_Auto Reload Test Assemblies" IsCheckable="True" IsChecked="{Binding AutoReloadAssemblies}" Command="{Binding AutoReloadAssembliesCommand}" />
+                <MenuItem
+                    Command="{Binding AutoReloadAssembliesCommand}"
+                    Header="_Auto Reload Test Assemblies"
+                    IsCheckable="True"
+                    IsChecked="{Binding AutoReloadAssemblies}" />
             </MenuItem>
             <MenuItem Header="_Project">
                 <MenuItem Header="_Open" />
@@ -86,10 +89,11 @@
                 <RowDefinition Height="auto" />
             </Grid.RowDefinitions>
 
-            <GroupBox Header="Refinements"
-                      Margin="3"
-                      Grid.Column="0"
-                      Grid.Row="0">
+            <GroupBox
+                Grid.Row="0"
+                Grid.Column="0"
+                Margin="3"
+                Header="Refinements">
                 <Grid>
                     <Grid.RowDefinitions>
                         <RowDefinition Height="auto" />
@@ -100,25 +104,24 @@
                         <RowDefinition Height="*" />
                     </Grid.RowDefinitions>
 
-                    <Label Content="Search:"
-                           Grid.Row="0" />
-                    <TextBox Grid.Row="1"
-                             Text="{Binding FilterString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+                    <Label Grid.Row="0" Content="Search:" />
+                    <TextBox Grid.Row="1" Text="{Binding FilterString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
 
-                    <Label Content="Assemblies:"
-                           Grid.Row="2" />
-                    <ListBox Height="175"
-                             ItemsSource="{Binding Assemblies}"
-                             SelectionMode="Extended"
-                             Grid.Row="3">
+                    <Label Grid.Row="2" Content="Assemblies:" />
+                    <ListBox
+                        Grid.Row="3"
+                        Height="175"
+                        ItemsSource="{Binding Assemblies}"
+                        SelectionMode="Extended">
                         <ListBox.ItemTemplate>
                             <DataTemplate DataType="vm:TestAssemblyViewModel">
                                 <StackPanel Orientation="Horizontal">
                                     <TextBlock Text="{Binding DisplayName}" />
 
-                                    <TextBlock Text=" Discovering tests..."
-                                               FontStyle="Italic"
-                                               Foreground="Gray">
+                                    <TextBlock
+                                        FontStyle="Italic"
+                                        Foreground="Gray"
+                                        Text=" Discovering tests...">
 
                                         <TextBlock.Style>
                                             <Style TargetType="TextBlock">
@@ -138,41 +141,36 @@
 
                         <ListBox.ItemContainerStyle>
                             <Style TargetType="{x:Type ListBoxItem}">
-                                <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=IsSelected}"/>
+                                <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=IsSelected}" />
                             </Style>
                         </ListBox.ItemContainerStyle>
 
                         <ListBox.ContextMenu>
                             <ContextMenu>
-                                <MenuItem Header="Reload" Command="{Binding AssemblyReloadCommand}" />
-                                <MenuItem Header="Reload All" Command="{Binding AssemblyReloadAllCommand}" />
+                                <MenuItem Command="{Binding AssemblyReloadCommand}" Header="Reload" />
+                                <MenuItem Command="{Binding AssemblyReloadAllCommand}" Header="Reload All" />
                                 <Separator />
-                                <MenuItem Header="Remove" Command="{Binding AssemblyRemoveCommand}" />
-                                <MenuItem Header="Remove All" Command="{Binding AssemblyRemoveAllCommand}" />
+                                <MenuItem Command="{Binding AssemblyRemoveCommand}" Header="Remove" />
+                                <MenuItem Command="{Binding AssemblyRemoveAllCommand}" Header="Remove All" />
                             </ContextMenu>
                         </ListBox.ContextMenu>
                     </ListBox>
 
-                    <Label Content="Traits:"
-                           Grid.Row="4" />
+                    <Label Grid.Row="4" Content="Traits:" />
 
-                    <TreeView Grid.Row="5"
-                              ItemsSource="{Binding Traits}">
+                    <TreeView Grid.Row="5" ItemsSource="{Binding Traits}">
 
                         <TreeView.Resources>
-                            <HierarchicalDataTemplate DataType="{x:Type vm:TraitViewModel}"
-                                                      ItemsSource="{Binding Children}">
+                            <HierarchicalDataTemplate DataType="{x:Type vm:TraitViewModel}" ItemsSource="{Binding Children}">
 
-                                <CheckBox IsChecked="{Binding IsChecked}" Content="{Binding Text}" >
+                                <CheckBox Content="{Binding Text}" IsChecked="{Binding IsChecked}">
                                     <i:Interaction.Triggers>
                                         <i:EventTrigger EventName="Checked">
-                                            <cmd:EventToCommand Command="{Binding DataContext.TraitCheckedChangedCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                                                CommandParameter="{Binding}" />
+                                            <cmd:EventToCommand Command="{Binding DataContext.TraitCheckedChangedCommand, RelativeSource={RelativeSource AncestorType=Window}}" CommandParameter="{Binding}" />
                                         </i:EventTrigger>
 
                                         <i:EventTrigger EventName="Unchecked">
-                                            <cmd:EventToCommand Command="{Binding DataContext.TraitCheckedChangedCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                                                CommandParameter="{Binding}" />
+                                            <cmd:EventToCommand Command="{Binding DataContext.TraitCheckedChangedCommand, RelativeSource={RelativeSource AncestorType=Window}}" CommandParameter="{Binding}" />
                                         </i:EventTrigger>
                                     </i:Interaction.Triggers>
                                 </CheckBox>
@@ -188,7 +186,7 @@
 
                         <TreeView.ContextMenu>
                             <ContextMenu>
-                                <MenuItem Header="Clear" Command="{Binding TraitsClearCommand}" />
+                                <MenuItem Command="{Binding TraitsClearCommand}" Header="Clear" />
                             </ContextMenu>
                         </TreeView.ContextMenu>
 
@@ -196,36 +194,40 @@
                 </Grid>
             </GroupBox>
 
-            <Grid Grid.Column="0"
-                  Grid.Row="1">
+            <Grid Grid.Row="1" Grid.Column="0">
                 <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="*" />
-                    <ColumnDefinition Width="*"/>
+                    <ColumnDefinition Width="*" />
                     <ColumnDefinition Width="*" />
                 </Grid.ColumnDefinitions>
 
-                <Button Content="_Run All"
-                        Command="{Binding RunAllCommand}"
-                        Grid.Column="0" Margin="10,0,0,0"/>
-                <Button Content="Run _Selected"
-                        Command="{Binding RunSelectedCommand}"
-                        Grid.Column="1"/>
-                <Button Content="_Cancel"
-                        Command="{Binding CancelCommand}"
-                        Grid.Column="2" Margin="0,0,10,0" />
+                <Button
+                    Grid.Column="0"
+                    Margin="10,0,0,0"
+                    Command="{Binding RunAllCommand}"
+                    Content="_Run All" />
+                <Button
+                    Grid.Column="1"
+                    Command="{Binding RunSelectedCommand}"
+                    Content="Run _Selected" />
+                <Button
+                    Grid.Column="2"
+                    Margin="0,0,10,0"
+                    Command="{Binding CancelCommand}"
+                    Content="_Cancel" />
             </Grid>
 
-            <Grid Grid.Column="1"
-                  Grid.Row="0">
+            <Grid Grid.Row="0" Grid.Column="1">
                 <Grid.RowDefinitions>
                     <RowDefinition Height="*" MinHeight="200px" />
                     <RowDefinition Height="auto" />
-                    <RowDefinition Height="*"  MinHeight="200px"/>
+                    <RowDefinition Height="*" MinHeight="200px" />
                 </Grid.RowDefinitions>
 
-                <GroupBox Header="{Binding TestCasesCaption}"
-                          Margin="3"
-                          Grid.Row="0">
+                <GroupBox
+                    Grid.Row="0"
+                    Margin="3"
+                    Header="{Binding TestCasesCaption}">
                     <Grid>
                         <Grid.RowDefinitions>
                             <RowDefinition Height="auto" />
@@ -233,71 +235,82 @@
                         </Grid.RowDefinitions>
 
                         <StackPanel Orientation="Horizontal">
-                            <ToggleButton IsChecked="{Binding FilterPassedTests}"
-                                          BorderThickness="0"
-                                          Background="Transparent"
-                                          Margin="0,4,2,4"
-                                          Grid.Column="0"
-                                          Command="{Binding TestFilterChanged}">
+                            <ToggleButton
+                                Grid.Column="0"
+                                Margin="0,4,2,4"
+                                Background="Transparent"
+                                BorderThickness="0"
+                                Command="{Binding TestFilterChanged}"
+                                IsChecked="{Binding FilterPassedTests}">
                                 <StackPanel Orientation="Horizontal">
                                     <Image Source="Artwork\Passed_large.png" />
-                                    <TextBlock Margin="4,0"
-                                               FontSize="16"
-                                               Text="{Binding TestsPassed, StringFormat={}{0:#\,0}}"
-                                               VerticalAlignment="Center" />
+                                    <TextBlock
+                                        Margin="4,0"
+                                        VerticalAlignment="Center"
+                                        FontSize="16"
+                                        Text="{Binding TestsPassed, StringFormat={}{0:#\,0}}" />
                                 </StackPanel>
                             </ToggleButton>
 
-                            <ToggleButton IsChecked="{Binding FilterFailedTests}"
-                                          BorderThickness="0"
-                                          Background="Transparent"
-                                          Margin="2,4"
-                                          Grid.Column="1"
-                                          Command="{Binding TestFilterChanged}">
+                            <ToggleButton
+                                Grid.Column="1"
+                                Margin="2,4"
+                                Background="Transparent"
+                                BorderThickness="0"
+                                Command="{Binding TestFilterChanged}"
+                                IsChecked="{Binding FilterFailedTests}">
                                 <StackPanel Orientation="Horizontal">
                                     <Image Source="Artwork\Failed_large.png" />
-                                    <TextBlock Margin="4,0"
-                                               FontSize="16"
-                                               Text="{Binding TestsFailed, StringFormat={}{0:#\,0}}"
-                                               VerticalAlignment="Center" />
+                                    <TextBlock
+                                        Margin="4,0"
+                                        VerticalAlignment="Center"
+                                        FontSize="16"
+                                        Text="{Binding TestsFailed, StringFormat={}{0:#\,0}}" />
                                 </StackPanel>
                             </ToggleButton>
 
-                            <ToggleButton IsChecked="{Binding FilterSkippedTests}"
-                                          BorderThickness="0"
-                                          Background="Transparent"
-                                          Margin="2,4,0,4"
-                                          Grid.Column="2"
-                                          Command="{Binding TestFilterChanged}">
+                            <ToggleButton
+                                Grid.Column="2"
+                                Margin="2,4,0,4"
+                                Background="Transparent"
+                                BorderThickness="0"
+                                Command="{Binding TestFilterChanged}"
+                                IsChecked="{Binding FilterSkippedTests}">
                                 <StackPanel Orientation="Horizontal">
                                     <Image Source="Artwork\Skipped_large.png" />
-                                    <TextBlock Margin="4,0"
-                                               FontSize="16"
-                                               Text="{Binding TestsSkipped, StringFormat={}{0:#\,0}}"
-                                               VerticalAlignment="Center" />
+                                    <TextBlock
+                                        Margin="4,0"
+                                        VerticalAlignment="Center"
+                                        FontSize="16"
+                                        Text="{Binding TestsSkipped, StringFormat={}{0:#\,0}}" />
                                 </StackPanel>
                             </ToggleButton>
 
-                            <ToggleButton IsChecked="{Binding FilterRunningTests}"
-                                          BorderThickness="0"
-                                          Background="Transparent"
-                                          Margin="2,4,0,4"
-                                          Grid.Column="2"
-                                          Command="{Binding TestFilterChanged}">
+                            <ToggleButton
+                                Grid.Column="2"
+                                Margin="2,4,0,4"
+                                Background="Transparent"
+                                BorderThickness="0"
+                                Command="{Binding TestFilterChanged}"
+                                IsChecked="{Binding FilterRunningTests}">
                                 <StackPanel Orientation="Horizontal">
                                     <Image Source="Artwork\Running_large.png" />
-                                    <TextBlock Margin="4,0"
-                                               FontSize="16"
-                                               Text="{Binding TestsRunning, StringFormat={}{0:#\,0}}"
-                                               VerticalAlignment="Center" />
+                                    <TextBlock
+                                        Margin="4,0"
+                                        VerticalAlignment="Center"
+                                        FontSize="16"
+                                        Text="{Binding TestsRunning, StringFormat={}{0:#\,0}}" />
                                 </StackPanel>
                             </ToggleButton>
                         </StackPanel>
 
-                        <ListBox x:Name="TestCases" ItemsSource="{Binding FilteredTestCases}"
-                                 SelectionMode="Extended"
-                                 SelectedItem="{Binding SelectedTestCase, Mode=TwoWay}"
-                                 Grid.Row="1" SelectionChanged="TestCases_SelectionChanged">
+                        <ListBox
+                            x:Name="TestCases"
+                            Grid.Row="1"
+                            ItemsSource="{Binding FilteredTestCases}"
+                            SelectedItem="{Binding SelectedTestCase, Mode=TwoWay}"
+                            SelectionChanged="TestCases_SelectionChanged"
+                            SelectionMode="Extended">
                             <ListBox.ItemTemplate>
                                 <DataTemplate DataType="vm:TestCaseViewModel">
                                     <Grid>
@@ -306,49 +319,71 @@
                                             <ColumnDefinition Width="*" />
                                         </Grid.ColumnDefinitions>
 
-                                        <Image Width="16"
-                                               Margin="0,0,2,0"
-                                               Source="{Binding Path=State, Mode=OneWay, Converter={StaticResource TestStateConverter}}"
-                                               Grid.Column="0" />
+                                        <Image
+                                            Grid.Column="0"
+                                            Width="16"
+                                            Margin="0,0,2,0"
+                                            Source="{Binding Path=State, Mode=OneWay, Converter={StaticResource TestStateConverter}}" />
 
-                                        <TextBlock Text="{Binding DisplayName}"
-                                                   VerticalAlignment="Center"
-                                                   Grid.Column="1" />
+                                        <TextBlock
+                                            Grid.Column="1"
+                                            VerticalAlignment="Center"
+                                            Text="{Binding DisplayName}" />
                                     </Grid>
                                 </DataTemplate>
                             </ListBox.ItemTemplate>
+                            <ListBox.InputBindings>
+                                <KeyBinding Key="Enter" Command="{Binding RunSelectedCommand}" />
+                            </ListBox.InputBindings>
+                            <i:Interaction.Triggers>
+                                <i:EventTrigger EventName="MouseDoubleClick">
+                                    <cmd:EventToCommand Command="{Binding Path=RunSelectedCommand}" PassEventArgsToCommand="False" />
+                                </i:EventTrigger>
+                            </i:Interaction.Triggers>
                         </ListBox>
                     </Grid>
                 </GroupBox>
 
-                <GridSplitter Grid.Row="1" HorizontalAlignment="Stretch" Height="3" Background="White"/>
+                <GridSplitter
+                    Grid.Row="1"
+                    Height="3"
+                    HorizontalAlignment="Stretch"
+                    Background="White" />
 
-                <GroupBox Header="Output"
-                          Margin="3"
-                          Grid.Row="2">
-                    <TextBox IsReadOnly="True"
-                             HorizontalScrollBarVisibility="Auto"
-                             VerticalScrollBarVisibility="Visible"
-                             FontFamily="Consolas"
-                             Text="{Binding Output}"/>
+                <GroupBox
+                    Grid.Row="2"
+                    Margin="3"
+                    Header="Output">
+                    <TextBox
+                        FontFamily="Consolas"
+                        HorizontalScrollBarVisibility="Auto"
+                        IsReadOnly="True"
+                        Text="{Binding Output}"
+                        VerticalScrollBarVisibility="Visible" />
                 </GroupBox>
             </Grid>
 
-            <GridSplitter Grid.Column="0" VerticalAlignment="Stretch" Width="3" Background="White"/>
+            <GridSplitter
+                Grid.Column="0"
+                Width="3"
+                VerticalAlignment="Stretch"
+                Background="White" />
 
-            <ProgressBar Foreground="{Binding Path=CurrentRunState, Converter={StaticResource TestStateConverter}, Mode=OneWay}"
-                         Minimum="0"
-                         Maximum="{Binding MaximumProgress}"
-                         Value="{Binding Path=TestsCompleted}"
-                         Grid.Column="1"
-                         Grid.Row="1"
-                         Margin="3" />
+            <ProgressBar
+                Grid.Row="1"
+                Grid.Column="1"
+                Margin="3"
+                Foreground="{Binding Path=CurrentRunState, Converter={StaticResource TestStateConverter}, Mode=OneWay}"
+                Maximum="{Binding MaximumProgress}"
+                Minimum="0"
+                Value="{Binding Path=TestsCompleted}" />
         </Grid>
 
         <StackPanel Grid.Row="2">
-            <Border BorderBrush="LightGray"
-                    BorderThickness="1"
-                    Margin="3" />
+            <Border
+                Margin="3"
+                BorderBrush="LightGray"
+                BorderThickness="1" />
             <StatusBar>
                 <StatusBar.ItemsPanel>
                     <ItemsPanelTemplate>
@@ -358,7 +393,7 @@
                                 <ColumnDefinition Width="auto" />
                                 <ColumnDefinition Width="auto" />
                                 <ColumnDefinition Width="auto" />
-                                <ColumnDefinition Width="16"/>
+                                <ColumnDefinition Width="16" />
                             </Grid.ColumnDefinitions>
                         </Grid>
                     </ItemsPanelTemplate>
@@ -366,28 +401,25 @@
 
                 <StatusBarItem Grid.Column="1">
                     <StackPanel Orientation="Horizontal">
-                        <TextBlock Text="Tests passed: "
-                                   Foreground="DarkGreen"/>
+                        <TextBlock Foreground="DarkGreen" Text="Tests passed: " />
 
-                        <TextBlock Text="{Binding TestsPassed, StringFormat={}{0:#\,0}}"/>
+                        <TextBlock Text="{Binding TestsPassed, StringFormat={}{0:#\,0}}" />
                     </StackPanel>
                 </StatusBarItem>
 
                 <StatusBarItem Grid.Column="2">
                     <StackPanel Orientation="Horizontal">
-                        <TextBlock Text="Tests failed: "
-                                   Foreground="DarkRed"/>
+                        <TextBlock Foreground="DarkRed" Text="Tests failed: " />
 
-                        <TextBlock Text="{Binding TestsFailed, StringFormat={}{0:#\,0}}"/>
+                        <TextBlock Text="{Binding TestsFailed, StringFormat={}{0:#\,0}}" />
                     </StackPanel>
                 </StatusBarItem>
 
                 <StatusBarItem Grid.Column="3">
                     <StackPanel Orientation="Horizontal">
-                        <TextBlock Text="Tests skipped: "
-                                   Foreground="DarkGoldenrod"/>
+                        <TextBlock Foreground="DarkGoldenrod" Text="Tests skipped: " />
 
-                        <TextBlock Text="{Binding TestsSkipped, StringFormat={}{0:#\,0}}"/>
+                        <TextBlock Text="{Binding TestsSkipped, StringFormat={}{0:#\,0}}" />
                     </StackPanel>
                 </StatusBarItem>
             </StatusBar>

xunit.runner.wpf/MainWindow.xaml.cs

@@ -11,12 +11,15 @@ namespace Xunit.Runner.Wpf
     {
         public static Window Instance { get; private set; }
 
+        // WPF generates fields that are marked as non-nullable, but not definitely initialized.
+#pragma warning disable CS8618
         public MainWindow()
         {
             Instance = this;
 
             InitializeComponent();
         }
+#pragma warning restore
 
         protected override void OnSourceInitialized(EventArgs e)
         {

xunit.runner.wpf/Persistence/Storage.cs

@@ -16,7 +16,7 @@ namespace Xunit.Runner.Wpf.Persistence
 
         private static IsolatedStorageFile GetStorageFile() => IsolatedStorageFile.GetUserStoreForDomain();
 
-        public static XmlTextReader OpenXmlFile(string fileName)
+        public static XmlTextReader? OpenXmlFile(string fileName)
         {
             var storage = GetStorageFile();
             if (!storage.FileExists(fileName))

xunit.runner.wpf/ViewModel/AssemblyAndConfigFile.cs

@@ -5,9 +5,9 @@ namespace Xunit.Runner.Wpf.ViewModel
     public class AssemblyAndConfigFile
     {
         public string AssemblyFileName { get; }
-        public string ConfigFileName { get; }
+        public string? ConfigFileName { get; }
 
-        public AssemblyAndConfigFile(string assemblyFileName, string configFileName)
+        public AssemblyAndConfigFile(string assemblyFileName, string? configFileName)
         {
             this.AssemblyFileName = Path.GetFullPath(assemblyFileName);
             if (configFileName != null)

xunit.runner.wpf/ViewModel/MainViewModel.cs

@@ -33,7 +33,7 @@ namespace Xunit.Runner.Wpf.ViewModel
 
         private CancellationTokenSource filterCancellationTokenSource = new CancellationTokenSource();
 
-        private CancellationTokenSource cancellationTokenSource;
+        private CancellationTokenSource? cancellationTokenSource;
         private bool isBusy;
         private SearchQuery searchQuery = new SearchQuery();
         private bool autoReloadAssemblies;
@@ -54,7 +54,7 @@ namespace Xunit.Runner.Wpf.ViewModel
 
         public ObservableCollection<RecentAssemblyViewModel> RecentAssemblies { get; } = new ObservableCollection<RecentAssemblyViewModel>();
 
-        private ImmutableList<TestCaseViewModel> testsToRun;
+        private ImmutableList<TestCaseViewModel>? testsToRun;
 
         public ICommand ExitCommand { get; }
         public ICommand WindowLoadedCommand { get; }
@@ -63,7 +63,6 @@ namespace Xunit.Runner.Wpf.ViewModel
         public RelayCommand RunSelectedCommand { get; }
         public RelayCommand CancelCommand { get; }
         public ICommand TraitCheckedChangedCommand { get; }
-        public ICommand TraitSelectionChangedCommand { get; }
         public ICommand TraitsClearCommand { get; }
         public ICommand AssemblyReloadCommand { get; }
         public ICommand AssemblyReloadAllCommand { get; }
@@ -215,8 +214,8 @@ namespace Xunit.Runner.Wpf.ViewModel
             get { return Assemblies.Where(x => x.IsSelected).ToList(); }
         }
 
-        private string testCasesCaption;
-        public string TestCasesCaption
+        private string? testCasesCaption;
+        public string? TestCasesCaption
         {
             get { return testCasesCaption; }
             private set { Set(ref testCasesCaption, value); }
@@ -234,8 +233,8 @@ namespace Xunit.Runner.Wpf.ViewModel
             }
         }
 
-        private TestCaseViewModel selectedTest;
-        public TestCaseViewModel SelectedTestCase
+        private TestCaseViewModel? selectedTest;
+        public TestCaseViewModel? SelectedTestCase
         {
             get { return selectedTest; }
 
@@ -401,7 +400,7 @@ namespace Xunit.Runner.Wpf.ViewModel
                     var taskList = new List<Task>();
                     foreach (var assembly in assemblies)
                     {
-                        taskList.Add(this.testUtil.Discover(assembly.AssemblyFileName, this.OnTestsDiscovered, this.cancellationTokenSource.Token));
+                        taskList.Add(this.testUtil.Discover(assembly.AssemblyFileName, this.OnTestsDiscovered, CancellationToken));
 
                         var assemblyViewModel = new TestAssemblyViewModel(assembly);
 
@@ -427,6 +426,11 @@ namespace Xunit.Runner.Wpf.ViewModel
             }
         }
 
+        private CancellationToken CancellationToken
+            => cancellationTokenSource == null
+                ? CancellationToken.None
+                : cancellationTokenSource.Token;
+
         public bool ReloadAssemblies(IEnumerable<string> assemblies)
         {
             if (IsBusy)
@@ -454,7 +458,7 @@ namespace Xunit.Runner.Wpf.ViewModel
                         var assemblyFileName = assemblyViewModel.FileName;
                         RemoveAssemblyTestCases(assemblyFileName);
 
-                        taskList.Add(this.testUtil.Discover(assemblyFileName, OnTestsDiscovered, cancellationTokenSource.Token));
+                        taskList.Add(this.testUtil.Discover(assemblyFileName, OnTestsDiscovered, CancellationToken));
                     }
 
                     return taskList;
@@ -549,7 +553,7 @@ namespace Xunit.Runner.Wpf.ViewModel
                 var assemblyFileName = enumerable.First();
                 enumerable = enumerable.Skip(1);
 
-                var configFileName = (string)null;
+                var configFileName = (string?)null;
                 if (IsConfigFile(enumerable.FirstOrDefault()))
                 {
                     configFileName = enumerable.First();
@@ -630,7 +634,7 @@ namespace Xunit.Runner.Wpf.ViewModel
                 Task task;
                 if (runAll)
                 {
-                    task = this.testUtil.RunAll(assemblyFileName, OnTestStateChange, this.cancellationTokenSource.Token);
+                    task = this.testUtil.RunAll(assemblyFileName, OnTestStateChange, CancellationToken);
                 }
                 else
                 {
@@ -644,7 +648,7 @@ namespace Xunit.Runner.Wpf.ViewModel
                         }
                     }
 
-                    task = this.testUtil.RunSpecific(assemblyFileName, builder.ToImmutable(), OnTestStateChange, this.cancellationTokenSource.Token);
+                    task = this.testUtil.RunSpecific(assemblyFileName, builder.ToImmutable(), OnTestStateChange, CancellationToken);
                 }
 
                 testSessionList.Add(task);
@@ -778,7 +782,7 @@ namespace Xunit.Runner.Wpf.ViewModel
         private void OnExecuteCancel()
         {
             Debug.Assert(CanExecuteCancel());
-            this.cancellationTokenSource.Cancel();
+            cancellationTokenSource?.Cancel();
         }
 
         private void OnExecuteTraitCheckedChanged(TraitViewModel trait)

xunit.runner.wpf/ViewModel/TraitViewModel.cs

@@ -7,7 +7,7 @@ namespace Xunit.Runner.Wpf.ViewModel
 {
     public partial class TraitViewModel : ViewModelBase
     {
-        private readonly TraitViewModel _parent;
+        private readonly TraitViewModel? _parent;
         private bool? _isChecked;
         private bool _isExpanded;
         private string _text;
@@ -19,7 +19,7 @@ namespace Xunit.Runner.Wpf.ViewModel
         {
         }
 
-        private TraitViewModel(TraitViewModel parent, string text)
+        private TraitViewModel(TraitViewModel? parent, string text)
         {
             this._parent = parent;
             this._isChecked = false;

xunit.runner.wpf/packages.config

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="CommonServiceLocator" version="1.3" targetFramework="net452" />
-  <package id="Microsoft.Net.Compilers" version="2.2.0" targetFramework="net46" developmentDependency="true" />
   <package id="MvvmLight" version="5.3.0.0" targetFramework="net46" />
   <package id="MvvmLightLibs" version="5.3.0.0" targetFramework="net46" />
   <package id="NuGet.CommandLine" version="2.8.3" targetFramework="net46" />

xunit.runner.wpf/xunit.runner.wpf.csproj

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props" Condition="Exists('..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props')" />
   <Import Project="..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.props" Condition="Exists('..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.props')" />
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -216,7 +215,6 @@
     </PropertyGroup>
     <Error Condition="!Exists('..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.props'))" />
     <Error Condition="!Exists('..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.targets'))" />
-    <Error Condition="!Exists('..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Microsoft.Net.Compilers.2.2.0\build\Microsoft.Net.Compilers.props'))" />
   </Target>
   <Import Project="..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.targets" Condition="Exists('..\packages\Tvl.NuGet.BuildTasks.1.0.0-alpha002\build\Tvl.NuGet.BuildTasks.targets')" />
 </Project>