Merge branch 'release/3.1' into merge/release/3.0-to-release/3.1\n\nCommit migrated from 9df988bece

src/Configuration.KeyPerFile/ref/Microsoft.Extensions.Configuration.KeyPerFile.csproj

@@ -1,15 +1,15 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.KeyPerFile.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.FileProviders.Physical"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.Configuration.KeyPerFile.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.Configuration.KeyPerFile.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.FileProviders.Physical"  />
   </ItemGroup>

src/Configuration.KeyPerFile/src/Microsoft.Extensions.Configuration.KeyPerFile.csproj

@@ -2,8 +2,8 @@
 
   <PropertyGroup>
     <Description>Configuration provider that uses files in a directory for Microsoft.Extensions.Configuration.</Description>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <IsPackable>true</IsPackable>
     <IsShipping>true</IsShipping>
   </PropertyGroup>

src/Configuration.KeyPerFile/test/Microsoft.Extensions.Configuration.KeyPerFile.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

src/FileProviders/Embedded/ref/Microsoft.Extensions.FileProviders.Embedded.csproj

@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.FileProviders.Embedded.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.FileProviders.Abstractions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.FileProviders.Embedded.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.FileProviders.Embedded.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.FileProviders.Abstractions"  />
   </ItemGroup>
 </Project>

src/FileProviders/Embedded/src/Microsoft.Extensions.FileProviders.Embedded.csproj

@@ -3,10 +3,10 @@
   <PropertyGroup>
     <RootNamespace>Microsoft.Extensions.FileProviders</RootNamespace>
     <Description>File provider for files in embedded resources for Microsoft.Extensions.FileProviders.</Description>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <NuspecFile>$(MSBuildProjectName).multitarget.nuspec</NuspecFile>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <NuspecFile Condition="'$(DotNetBuildFromSource)' == 'true'">$(MSBuildProjectName).netcoreapp3.0.nuspec</NuspecFile>
+    <NuspecFile Condition="'$(DotNetBuildFromSource)' == 'true'">$(MSBuildProjectName).netcoreapp.nuspec</NuspecFile>
     <IsPackable>true</IsPackable>
     <IsShipping>true</IsShipping>
   </PropertyGroup>
@@ -27,9 +27,7 @@
 
   <ItemGroup>
     <NuspecProperty Include="AssemblyName=$(AssemblyName)" />
-    <NuspecProperty Include="OutputBinary=$(OutputPath)**\$(AssemblyName).dll" />
+    <NuspecProperty Include="OutputPath=$(OutputPath)" />
-    <NuspecProperty Include="OutputSymbol=$(OutputPath)**\$(AssemblyName).pdb" />
-    <NuspecProperty Include="OutputDocumentation=$(OutputPath)**\$(AssemblyName).xml" />
     <NuspecProperty Include="TaskAssemblyNetStandard=$(ArtifactsDir)bin\$(AssemblyName).Manifest.Task\$(Configuration)\netstandard2.0\$(AssemblyName).Manifest.Task.dll"/>
     <NuspecProperty Include="TaskSymbolNetStandard=$(ArtifactsDir)bin\$(AssemblyName).Manifest.Task\$(Configuration)\netstandard2.0\$(AssemblyName).Manifest.Task.pdb" Condition="'$(DebugType)'!='embedded'"/>
     <NuspecProperty Include="PackageIcon=$(PackageIconFullPath)" />

src/FileProviders/Embedded/src/Microsoft.Extensions.FileProviders.Embedded.multitarget.nuspec

@@ -3,7 +3,7 @@
   <metadata>
     $CommonMetadataElements$
     <dependencies>
-      <group targetFramework=".NETCoreApp3.0">
+      <group targetFramework=".NETCoreApp3.1">
         <dependency id="Microsoft.Extensions.FileProviders.Abstractions" version="$version$" exclude="Build,Analyzers" />
       </group>
       <group targetFramework=".NETStandard2.0">
@@ -14,9 +14,9 @@
   </metadata>
 
   <files>
-    <file src="$OutputBinary$" target="lib\" />
+    <file src="$OutputPath$**\$AssemblyName$.dll" target="lib\" />
-    <file src="$OutputSymbol$" target="lib\" />
+    <file src="$OutputPath$**\$AssemblyName$.pdb" target="lib\" />
-    <file src="$OutputDocumentation$" target="lib\" />
+    <file src="$OutputPath$**\$AssemblyName$.xml" target="lib\" />
     <file src="build\**\*" target="build\" />
     <file src="buildMultiTargeting\**\*" target="buildMultiTargeting\" />
     <file src="$PackageIcon$" target="" />

src/FileProviders/Embedded/src/Microsoft.Extensions.FileProviders.Embedded.netcoreapp.nuspec

@@ -3,7 +3,7 @@
   <metadata>
     $CommonMetadataElements$
     <dependencies>
-      <group targetFramework=".NETCoreApp3.0">
+      <group targetFramework=".NETCoreApp3.1">
         <dependency id="Microsoft.Extensions.FileProviders.Abstractions" version="$version$" exclude="Build,Analyzers" />
       </group>
     </dependencies>
@@ -11,9 +11,9 @@
   </metadata>
 
   <files>
-    <file src="$OutputBinary$" target="lib\" />
+    <file src="$OutputPath$**\$AssemblyName$.dll" target="lib\" />
-    <file src="$OutputSymbol$" target="lib\" />
+    <file src="$OutputPath$**\$AssemblyName$.pdb" target="lib\" />
-    <file src="$OutputDocumentation$" target="lib\" />
+    <file src="$OutputPath$**\$AssemblyName$.xml" target="lib\" />
     <file src="build\**\*" target="build\" />
     <file src="buildMultiTargeting\**\*" target="buildMultiTargeting\" />
     <file src="$PackageIcon$" target="" />

src/FileProviders/Embedded/test/Microsoft.Extensions.FileProviders.Embedded.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

src/FileProviders/Manifest.MSBuildTask/test/Microsoft.Extensions.FileProviders.Embedded.Manifest.Task.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

src/HealthChecks/Abstractions/ref/Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions.csproj

@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions.netstandard2.0.cs" />
     
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions.netcoreapp.cs" />
     
   </ItemGroup>
 </Project>

src/HealthChecks/Abstractions/src/Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions.csproj

@@ -7,8 +7,8 @@ Commonly Used Types
 Microsoft.Extensions.Diagnostics.HealthChecks.IHealthCheck
     </Description>
     <RootNamespace>Microsoft.Extensions.Diagnostics.HealthChecks</RootNamespace>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>diagnostics;healthchecks</PackageTags>

src/HealthChecks/HealthChecks/ref/Microsoft.Extensions.Diagnostics.HealthChecks.csproj

@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Diagnostics.HealthChecks.netstandard2.0.cs" />
@@ -9,8 +9,8 @@
     <Reference Include="Microsoft.Extensions.Hosting.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.Diagnostics.HealthChecks.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.Diagnostics.HealthChecks.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Hosting.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />

src/HealthChecks/HealthChecks/src/Microsoft.Extensions.Diagnostics.HealthChecks.csproj

@@ -6,8 +6,8 @@ Commonly Used Types:
 Microsoft.Extensions.Diagnostics.HealthChecks.HealthCheckService
 Microsoft.Extensions.Diagnostics.HealthChecks.IHealthChecksBuilder
     </Description>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>diagnostics;healthchecks</PackageTags>

src/HealthChecks/HealthChecks/test/Microsoft.Extensions.Diagnostics.HealthChecks.Tests.csproj

@@ -3,7 +3,7 @@
   <Import Project="$(RepoRoot)src\Logging\Logging.Testing\src\build\Microsoft.Extensions.Logging.Testing.props" />
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <RootNamespace>Microsoft.Extensions.Diagnostics.HealthChecks</RootNamespace>
   </PropertyGroup>
 

src/JSInterop/Microsoft.JSInterop/ref/Microsoft.JSInterop.csproj

@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.JSInterop.netstandard2.0.cs" />
     <Reference Include="System.Text.Json"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.JSInterop.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.JSInterop.netcoreapp.cs" />
     
   </ItemGroup>
 </Project>

src/JSInterop/Microsoft.JSInterop/src/DotNetObjectReference.cs

@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+
 namespace Microsoft.JSInterop
 {
     /// <summary>
@@ -15,6 +17,11 @@ namespace Microsoft.JSInterop
         /// <returns>An instance of <see cref="DotNetObjectReference{TValue}" />.</returns>
         public static DotNetObjectReference<TValue> Create<TValue>(TValue value) where TValue : class
         {
+            if (value is null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
             return new DotNetObjectReference<TValue>(value);
         }
     }

src/JSInterop/Microsoft.JSInterop/src/Infrastructure/DotNetDispatcher.cs

@@ -24,6 +24,9 @@ namespace Microsoft.JSInterop.Infrastructure
         private static readonly ConcurrentDictionary<AssemblyKey, IReadOnlyDictionary<string, (MethodInfo, Type[])>> _cachedMethodsByAssembly
             = new ConcurrentDictionary<AssemblyKey, IReadOnlyDictionary<string, (MethodInfo, Type[])>>();
 
+        private static readonly ConcurrentDictionary<Type, IReadOnlyDictionary<string, (MethodInfo, Type[])>> _cachedMethodsByType
+            = new ConcurrentDictionary<Type, IReadOnlyDictionary<string, (MethodInfo, Type[])>>();
+
         /// <summary>
         /// Receives a call from JS to .NET, locating and invoking the specified method.
         /// </summary>
@@ -129,9 +132,12 @@ namespace Microsoft.JSInterop.Infrastructure
             var methodIdentifier = callInfo.MethodIdentifier;
 
             AssemblyKey assemblyKey;
+            MethodInfo methodInfo;
+            Type[] parameterTypes;
             if (objectReference is null)
             {
                 assemblyKey = new AssemblyKey(assemblyName);
+                (methodInfo, parameterTypes) = GetCachedMethodInfo(assemblyKey, methodIdentifier);
             }
             else
             {
@@ -147,11 +153,9 @@ namespace Microsoft.JSInterop.Infrastructure
                     return default;
                 }
 
-                assemblyKey = new AssemblyKey(objectReference.Value.GetType().Assembly);
+                (methodInfo, parameterTypes) = GetCachedMethodInfo(objectReference, methodIdentifier);
             }
 
-            var (methodInfo, parameterTypes) = GetCachedMethodInfo(assemblyKey, methodIdentifier);
-
             var suppliedArgs = ParseArguments(jsRuntime, methodIdentifier, argsJson, parameterTypes);
 
             try
@@ -301,7 +305,47 @@ namespace Microsoft.JSInterop.Infrastructure
             }
             else
             {
-                throw new ArgumentException($"The assembly '{assemblyKey.AssemblyName}' does not contain a public method with [{nameof(JSInvokableAttribute)}(\"{methodIdentifier}\")].");
+                throw new ArgumentException($"The assembly '{assemblyKey.AssemblyName}' does not contain a public invokable method with [{nameof(JSInvokableAttribute)}(\"{methodIdentifier}\")].");
+            }
+        }
+
+        private static (MethodInfo methodInfo, Type[] parameterTypes) GetCachedMethodInfo(IDotNetObjectReference objectReference, string methodIdentifier)
+        {
+            var type = objectReference.Value.GetType();
+            var assemblyMethods = _cachedMethodsByType.GetOrAdd(type, ScanTypeForCallableMethods);
+            if (assemblyMethods.TryGetValue(methodIdentifier, out var result))
+            {
+                return result;
+            }
+            else
+            {
+                throw new ArgumentException($"The type '{type.Name}' does not contain a public invokable method with [{nameof(JSInvokableAttribute)}(\"{methodIdentifier}\")].");
+            }
+
+            static Dictionary<string, (MethodInfo, Type[])> ScanTypeForCallableMethods(Type type)
+            {
+                var result = new Dictionary<string, (MethodInfo, Type[])>(StringComparer.Ordinal);
+                var invokableMethods = type
+                    .GetMethods(BindingFlags.Public | BindingFlags.Instance)
+                    .Where(method => !method.ContainsGenericParameters && method.IsDefined(typeof(JSInvokableAttribute), inherit: false));
+
+                foreach (var method in invokableMethods)
+                {
+                    var identifier = method.GetCustomAttribute<JSInvokableAttribute>(false).Identifier ?? method.Name;
+                    var parameterTypes = method.GetParameters().Select(p => p.ParameterType).ToArray();
+
+                    if (result.ContainsKey(identifier))
+                    {
+                        throw new InvalidOperationException($"The type {type.Name} contains more than one " +
+                            $"[JSInvokable] method with identifier '{identifier}'. All [JSInvokable] methods within the same " +
+                            $"type must have different identifiers. You can pass a custom identifier as a parameter to " +
+                            $"the [JSInvokable] attribute.");
+                    }
+
+                    result.Add(identifier, (method, parameterTypes));
+                }
+
+                return result;
             }
         }
 
@@ -312,35 +356,22 @@ namespace Microsoft.JSInterop.Infrastructure
             var result = new Dictionary<string, (MethodInfo, Type[])>(StringComparer.Ordinal);
             var invokableMethods = GetRequiredLoadedAssembly(assemblyKey)
                 .GetExportedTypes()
-                .SelectMany(type => type.GetMethods(
+                .SelectMany(type => type.GetMethods(BindingFlags.Public | BindingFlags.Static))
-                    BindingFlags.Public |
+                .Where(method => !method.ContainsGenericParameters && method.IsDefined(typeof(JSInvokableAttribute), inherit: false));
-                    BindingFlags.DeclaredOnly |
-                    BindingFlags.Instance |
-                    BindingFlags.Static))
-                .Where(method => method.IsDefined(typeof(JSInvokableAttribute), inherit: false));
             foreach (var method in invokableMethods)
             {
                 var identifier = method.GetCustomAttribute<JSInvokableAttribute>(false).Identifier ?? method.Name;
                 var parameterTypes = method.GetParameters().Select(p => p.ParameterType).ToArray();
 
-                try
+                if (result.ContainsKey(identifier))
                 {
-                    result.Add(identifier, (method, parameterTypes));
+                    throw new InvalidOperationException($"The assembly '{assemblyKey.AssemblyName}' contains more than one " +
-                }
+                        $"[JSInvokable] method with identifier '{identifier}'. All [JSInvokable] methods within the same " +
-                catch (ArgumentException)
+                        $"assembly must have different identifiers. You can pass a custom identifier as a parameter to " +
-                {
+                        $"the [JSInvokable] attribute.");
-                    if (result.ContainsKey(identifier))
-                    {
-                        throw new InvalidOperationException($"The assembly '{assemblyKey.AssemblyName}' contains more than one " +
-                            $"[JSInvokable] method with identifier '{identifier}'. All [JSInvokable] methods within the same " +
-                            $"assembly must have different identifiers. You can pass a custom identifier as a parameter to " +
-                            $"the [JSInvokable] attribute.");
-                    }
-                    else
-                    {
-                        throw;
-                    }
                 }
+
+                result.Add(identifier, (method, parameterTypes));
             }
 
             return result;

src/JSInterop/Microsoft.JSInterop/src/Microsoft.JSInterop.csproj

@@ -1,8 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <Description>Abstractions and features for interop between .NET and JavaScript code.</Description>
     <PackageTags>javascript;interop</PackageTags>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>

src/JSInterop/Microsoft.JSInterop/test/Infrastructure/DotNetDispatcherTest.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Linq;
-using System.Runtime.ExceptionServices;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -70,7 +69,7 @@ namespace Microsoft.JSInterop.Infrastructure
                 DotNetDispatcher.Invoke(new TestJSRuntime(), new DotNetInvocationInfo(thisAssemblyName, methodIdentifier, default, default), null);
             });
 
-            Assert.Equal($"The assembly '{thisAssemblyName}' does not contain a public method with [JSInvokableAttribute(\"{methodIdentifier}\")].", ex.Message);
+            Assert.Equal($"The assembly '{thisAssemblyName}' does not contain a public invokable method with [JSInvokableAttribute(\"{methodIdentifier}\")].", ex.Message);
         }
 
         [Fact]
@@ -355,6 +354,78 @@ namespace Microsoft.JSInterop.Infrastructure
             Assert.Equal("MY STRING", resultDto.StringVal);
         }
 
+        [Fact]
+        public void CanInvokeNonGenericInstanceMethodOnGenericType()
+        {
+            var jsRuntime = new TestJSRuntime();
+            var targetInstance = new GenericType<int>();
+            jsRuntime.Invoke<object>("_setup",
+                DotNetObjectReference.Create(targetInstance));
+            var argsJson = "[\"hello world\"]";
+
+            // Act
+            var resultJson = DotNetDispatcher.Invoke(jsRuntime, new DotNetInvocationInfo(null, nameof(GenericType<int>.EchoStringParameter), 1, default), argsJson);
+
+            // Assert
+            Assert.Equal("\"hello world\"", resultJson);
+        }
+
+        [Fact]
+        public void CanInvokeMethodsThatAcceptGenericParametersOnGenericTypes()
+        {
+            var jsRuntime = new TestJSRuntime();
+            var targetInstance = new GenericType<string>();
+            jsRuntime.Invoke<object>("_setup",
+                DotNetObjectReference.Create(targetInstance));
+            var argsJson = "[\"hello world\"]";
+
+            // Act
+            var resultJson = DotNetDispatcher.Invoke(jsRuntime, new DotNetInvocationInfo(null, nameof(GenericType<string>.EchoParameter), 1, default), argsJson);
+
+            // Assert
+            Assert.Equal("\"hello world\"", resultJson);
+        }
+
+        [Fact]
+        public void CannotInvokeStaticOpenGenericMethods()
+        {
+            var methodIdentifier = "StaticGenericMethod";
+            var jsRuntime = new TestJSRuntime();
+
+            // Act
+            var ex = Assert.Throws<ArgumentException>(() => DotNetDispatcher.Invoke(jsRuntime, new DotNetInvocationInfo(thisAssemblyName, methodIdentifier, 0, default), "[7]"));
+            Assert.Contains($"The assembly '{thisAssemblyName}' does not contain a public invokable method with [{nameof(JSInvokableAttribute)}(\"{methodIdentifier}\")].", ex.Message);
+        }
+
+        [Fact]
+        public void CannotInvokeInstanceOpenGenericMethods()
+        {
+            var methodIdentifier = "InstanceGenericMethod";
+            var targetInstance = new GenericType<int>();
+            var jsRuntime = new TestJSRuntime();
+            jsRuntime.Invoke<object>("_setup",
+                DotNetObjectReference.Create(targetInstance));
+            var argsJson = "[\"hello world\"]";
+
+            // Act
+            var ex = Assert.Throws<ArgumentException>(() => DotNetDispatcher.Invoke(jsRuntime, new DotNetInvocationInfo(null, methodIdentifier, 1, default), argsJson));
+            Assert.Contains($"The type 'GenericType`1' does not contain a public invokable method with [{nameof(JSInvokableAttribute)}(\"{methodIdentifier}\")].", ex.Message);
+        }
+
+        [Fact]
+        public void CannotInvokeMethodsWithGenericParameters_IfTypesDoNotMatch()
+        {
+            var jsRuntime = new TestJSRuntime();
+            var targetInstance = new GenericType<int>();
+            jsRuntime.Invoke<object>("_setup",
+                DotNetObjectReference.Create(targetInstance));
+            var argsJson = "[\"hello world\"]";
+
+            // Act & Assert
+            Assert.Throws<JsonException>(() =>
+                DotNetDispatcher.Invoke(jsRuntime, new DotNetInvocationInfo(null, nameof(GenericType<int>.EchoParameter), 1, default), argsJson));
+        }
+
         [Fact]
         public void CannotInvokeWithFewerNumberOfParameters()
         {
@@ -790,6 +861,18 @@ namespace Microsoft.JSInterop.Infrastructure
             }
         }
 
+        public class GenericType<TValue>
+        {
+            [JSInvokable] public string EchoStringParameter(string input) => input;
+            [JSInvokable] public TValue EchoParameter(TValue input) => input;
+        }
+
+        public class GenericMethodClass
+        {
+            [JSInvokable("StaticGenericMethod")] public static string StaticGenericMethod<TValue>(TValue input) => input.ToString();
+            [JSInvokable("InstanceGenericMethod")] public string GenericMethod<TValue>(TValue input) => input.ToString();
+        }
+
         public class TestJSRuntime : JSInProcessRuntime
         {
             private TaskCompletionSource<object> _nextInvocationTcs = new TaskCompletionSource<object>();

src/JSInterop/Microsoft.JSInterop/test/Microsoft.JSInterop.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

src/Localization/Abstractions/ref/Microsoft.Extensions.Localization.Abstractions.csproj

@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Localization.Abstractions.netstandard2.0.cs" />
     
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.Localization.Abstractions.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.Localization.Abstractions.netcoreapp.cs" />
     
   </ItemGroup>
 </Project>

src/Localization/Abstractions/src/Microsoft.Extensions.Localization.Abstractions.csproj

@@ -6,8 +6,8 @@
 Commonly used types:
 Microsoft.Extensions.Localization.IStringLocalizer
 Microsoft.Extensions.Localization.IStringLocalizer&lt;T&gt;</Description>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>localization</PackageTags>

src/Localization/Localization/ref/Microsoft.Extensions.Localization.csproj

@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Localization.netstandard2.0.cs" />
@@ -10,8 +10,8 @@
     <Reference Include="Microsoft.Extensions.Localization.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Logging.Abstractions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.Localization.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.Localization.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
     <Reference Include="Microsoft.Extensions.Localization.Abstractions"  />

src/Localization/Localization/src/Microsoft.Extensions.Localization.csproj

@@ -3,8 +3,8 @@
   <PropertyGroup>
     <Product>Microsoft .NET Extensions</Product>
     <Description>Application localization services and default implementation based on ResourceManager to load localized assembly resources.</Description>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>localization</PackageTags>

src/Localization/Localization/test/Microsoft.Extensions.Localization.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

src/ObjectPool/test/Microsoft.Extensions.ObjectPool.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

src/Shared/ActivatorUtilities/ActivatorUtilities.cs

@@ -402,7 +402,7 @@ namespace Microsoft.Extensions.Internal
                     }
                 }
 
-#if NETCOREAPP3_0
+#if NETCOREAPP
                 return _constructor.Invoke(BindingFlags.DoNotWrapExceptions, binder: null, parameters: _parameterValues, culture: null);
 #else
                 try

src/Shared/BenchmarkRunner/DefaultCoreConfig.cs

@@ -30,8 +30,12 @@ namespace BenchmarkDotNet.Attributes
             Add(Job.Core
 #if NETCOREAPP2_1
                 .With(CsProjCoreToolchain.From(NetCoreAppSettings.NetCoreApp21))
-#else
+#elif NETCOREAPP3_0
                 .With(CsProjCoreToolchain.From(new NetCoreAppSettings("netcoreapp3.0", null, ".NET Core 3.0")))
+#elif NETCOREAPP3_1
+                .With(CsProjCoreToolchain.From(new NetCoreAppSettings("netcoreapp3.1", null, ".NET Core 3.1")))
+#else
+#error Target frameworks need to be updated.
 #endif
                 .With(new GcMode { Server = true })
                 .With(RunStrategy.Throughput));

src/Shared/test/Shared.Tests/DotNetMuxerTests.cs

@@ -1,7 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#if NETCOREAPP3_0
+#if NETCOREAPP
 using System.IO;
 using System.Runtime.InteropServices;
 using Xunit;

src/Shared/test/Shared.Tests/Microsoft.AspNetCore.Shared.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
 

src/Shared/test/testassets/BuildWebHostInvalidSignature/BuildWebHostInvalidSignature.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

src/Shared/test/testassets/BuildWebHostPatternTestSite/BuildWebHostPatternTestSite.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

src/Shared/test/testassets/CreateHostBuilderInvalidSignature/CreateHostBuilderInvalidSignature.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

src/Shared/test/testassets/CreateHostBuilderPatternTestSite/CreateHostBuilderPatternTestSite.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

src/Shared/test/testassets/CreateWebHostBuilderInvalidSignature/CreateWebHostBuilderInvalidSignature.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

src/Shared/test/testassets/CreateWebHostBuilderPatternTestSite/CreateWebHostBuilderPatternTestSite.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

src/Shared/test/testassets/MockHostTypes/MockHostTypes.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
 </Project>

src/Testing/src/ITestMethodLifecycle.cs

@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    /// <summary>
+    /// Defines a lifecycle for attributes or classes that want to know about tests starting
+    /// or ending. Implement this on a test class, or attribute at the method/class/assembly level.
+    /// </summary>
+    /// <remarks>
+    /// Requires defining <see cref="AspNetTestFramework"/> as the test framework.
+    /// </remarks>
+    public interface ITestMethodLifecycle
+    {
+        Task OnTestStartAsync(TestContext context, CancellationToken cancellationToken);
+
+        Task OnTestEndAsync(TestContext context, Exception exception, CancellationToken cancellationToken);
+    }
+}

src/Testing/src/RepeatAttribute.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.ComponentModel;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    /// <summary>
+    /// Runs a test multiple times to stress flaky tests that are believed to be fixed.
+    /// This can be used on an assembly, class, or method name. Requires using the AspNetCore test framework.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class | AttributeTargets.Assembly, AllowMultiple = false)]
+    public class RepeatAttribute : Attribute
+    {
+        public RepeatAttribute(int runCount = 10)
+        {
+            RunCount = runCount;
+        }
+
+        /// <summary>
+        /// The number of times to run a test.
+        /// </summary>
+        public int RunCount { get; }
+    }
+}

src/Testing/src/RepeatContext.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Threading;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class RepeatContext
+    {
+        private static AsyncLocal<RepeatContext> _current = new AsyncLocal<RepeatContext>();
+
+        public static RepeatContext Current
+        {
+            get => _current.Value;
+            internal set => _current.Value = value;
+        }
+
+        public RepeatContext(int limit)
+        {
+            Limit = limit;
+        }
+
+        public int Limit { get; }
+
+        public int CurrentIteration { get; set; }
+    }
+}

src/Testing/src/ShortClassNameAttribute.cs

@@ -0,0 +1,17 @@
+// Copyright(c) .NET Foundation.All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    /// <summary>
+    /// Used to specify that <see cref="TestFileOutputContext.TestClassName"/> should used the
+    /// unqualified class name. This is needed when a fully-qualified class name exceeds
+    /// max path for logging.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Assembly, AllowMultiple = false)]
+    public class ShortClassNameAttribute : Attribute
+    {
+    }
+}

src/Testing/src/TestContext.cs

@@ -0,0 +1,44 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Reflection;
+using Xunit.Abstractions;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    /// <summary>
+    /// Provides access to contextual information about the running tests. Get access by
+    /// implementing <see cref="ITestMethodLifecycle"/>.
+    /// </summary>
+    /// <remarks>
+    /// Requires defining <see cref="AspNetTestFramework"/> as the test framework.
+    /// </remarks>
+    public sealed class TestContext
+    {
+        private Lazy<TestFileOutputContext> _files;
+
+        public TestContext(
+            Type testClass,
+            object[] constructorArguments,
+            MethodInfo testMethod,
+            object[] methodArguments,
+            ITestOutputHelper output)
+        {
+            TestClass = testClass;
+            ConstructorArguments = constructorArguments;
+            TestMethod = testMethod;
+            MethodArguments = methodArguments;
+            Output = output;
+
+            _files = new Lazy<TestFileOutputContext>(() => new TestFileOutputContext(this));
+        }
+
+        public Type TestClass { get; }
+        public MethodInfo TestMethod { get; }
+        public object[] ConstructorArguments { get; }
+        public object[] MethodArguments { get; }
+        public ITestOutputHelper Output { get; }
+        public TestFileOutputContext FileOutput => _files.Value;
+    }
+}

src/Testing/src/TestFileOutputContext.cs

@@ -0,0 +1,140 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    /// <summary>
+    /// Provides access to file storage for the running test. Get access by
+    /// implementing <see cref="ITestMethodLifecycle"/>, and accessing <see cref="TestContext.FileOutput"/>.
+    /// </summary>
+    /// <remarks>
+    /// Requires defining <see cref="AspNetTestFramework"/> as the test framework.
+    /// </remarks>
+    public sealed class TestFileOutputContext
+    {
+        private static char[] InvalidFileChars = new char[]
+        {
+            '\"', '<', '>', '|', '\0',
+            (char)1, (char)2, (char)3, (char)4, (char)5, (char)6, (char)7, (char)8, (char)9, (char)10,
+            (char)11, (char)12, (char)13, (char)14, (char)15, (char)16, (char)17, (char)18, (char)19, (char)20,
+            (char)21, (char)22, (char)23, (char)24, (char)25, (char)26, (char)27, (char)28, (char)29, (char)30,
+            (char)31, ':', '*', '?', '\\', '/', ' ', (char)127
+        };
+
+        private readonly TestContext _parent;
+
+        public TestFileOutputContext(TestContext parent)
+        {
+            _parent = parent;
+
+            TestName = GetTestMethodName(parent.TestMethod, parent.MethodArguments);
+            TestClassName = GetTestClassName(parent.TestClass);
+
+            AssemblyOutputDirectory = GetAssemblyBaseDirectory(_parent.TestClass.Assembly);
+            if (!string.IsNullOrEmpty(AssemblyOutputDirectory))
+            {
+                TestClassOutputDirectory = Path.Combine(AssemblyOutputDirectory, TestClassName);
+            }
+        }
+
+        public string TestName { get; }
+
+        public string TestClassName { get; }
+
+        public string AssemblyOutputDirectory { get; }
+
+        public string TestClassOutputDirectory { get; }
+
+        public string GetUniqueFileName(string prefix, string extension)
+        {
+            if (prefix == null)
+            {
+                throw new ArgumentNullException(nameof(prefix));
+            }
+
+            if (extension != null && !extension.StartsWith(".", StringComparison.Ordinal))
+            {
+                throw new ArgumentException("The extension must start with '.' if one is provided.", nameof(extension));
+            }
+
+            var path = Path.Combine(TestClassOutputDirectory, $"{prefix}{extension}");
+
+            var i = 1;
+            while (File.Exists(path))
+            {
+                path = Path.Combine(TestClassOutputDirectory, $"{prefix}{i++}{extension}");
+            }
+
+            return path;
+        }
+
+        // Gets the output directory without appending the TFM or assembly name.
+        public static string GetOutputDirectory(Assembly assembly)
+        {
+            var attribute = assembly.GetCustomAttributes().OfType<TestOutputDirectoryAttribute>().FirstOrDefault();
+            return attribute?.BaseDirectory;
+        }
+
+        public static string GetAssemblyBaseDirectory(Assembly assembly, string baseDirectory = null)
+        {
+            var attribute = assembly.GetCustomAttributes().OfType<TestOutputDirectoryAttribute>().FirstOrDefault();
+            baseDirectory = baseDirectory ?? attribute?.BaseDirectory;
+            if (string.IsNullOrEmpty(baseDirectory))
+            {
+                return string.Empty;
+            }
+
+            return Path.Combine(baseDirectory, assembly.GetName().Name, attribute.TargetFramework);
+        }
+
+        public static string GetTestClassName(Type type)
+        {
+            var shortNameAttribute =
+                type.GetCustomAttribute<ShortClassNameAttribute>() ??
+                type.Assembly.GetCustomAttribute<ShortClassNameAttribute>();
+            var name = shortNameAttribute == null ? type.FullName : type.Name;
+
+            // Try to shorten the class name using the assembly name
+            var assemblyName = type.Assembly.GetName().Name;
+            if (name.StartsWith(assemblyName + "."))
+            {
+                name = name.Substring(assemblyName.Length + 1);
+            }
+
+            return name;
+        }
+
+        public static string GetTestMethodName(MethodInfo method, object[] arguments)
+        {
+            var name = arguments.Aggregate(method.Name, (a, b) => $"{a}-{(b ?? "null")}");
+            return RemoveIllegalFileChars(name);
+        }
+
+        public static string RemoveIllegalFileChars(string s)
+        {
+            var sb = new StringBuilder();
+
+            foreach (var c in s)
+            {
+                if (InvalidFileChars.Contains(c))
+                {
+                    if (sb.Length > 0 && sb[sb.Length - 1] != '_')
+                    {
+                        sb.Append('_');
+                    }
+                }
+                else
+                {
+                    sb.Append(c);
+                }
+            }
+            return sb.ToString();
+        }
+    }
+}

src/Testing/src/TestOutputDirectoryAttribute.cs

@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false, Inherited = true)]
+    public class TestOutputDirectoryAttribute : Attribute
+    {
+        public TestOutputDirectoryAttribute(string targetFramework, string baseDirectory = null)
+        {
+            TargetFramework = targetFramework;
+            BaseDirectory = baseDirectory;
+        }
+
+        public string BaseDirectory { get; }
+        public string TargetFramework { get; }
+    }
+}

src/Testing/src/xunit/AspNetTestAssemblyRunner.cs

@@ -0,0 +1,83 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class AspNetTestAssemblyRunner : XunitTestAssemblyRunner
+    {
+        private readonly Dictionary<Type, object> _assemblyFixtureMappings = new Dictionary<Type, object>();
+
+        public AspNetTestAssemblyRunner(
+            ITestAssembly testAssembly,
+            IEnumerable<IXunitTestCase> testCases,
+            IMessageSink diagnosticMessageSink,
+            IMessageSink executionMessageSink,
+            ITestFrameworkExecutionOptions executionOptions)
+            : base(testAssembly, testCases, diagnosticMessageSink, executionMessageSink, executionOptions)
+        {
+        }
+
+        protected override async Task AfterTestAssemblyStartingAsync()
+        {
+            await base.AfterTestAssemblyStartingAsync();
+
+            // Find all the AssemblyFixtureAttributes on the test assembly
+            Aggregator.Run(() =>
+            {
+                var fixturesAttributes = ((IReflectionAssemblyInfo)TestAssembly.Assembly)
+                    .Assembly
+                    .GetCustomAttributes(typeof(AssemblyFixtureAttribute), false)
+                    .Cast<AssemblyFixtureAttribute>()
+                    .ToList();
+
+                // Instantiate all the fixtures
+                foreach (var fixtureAttribute in fixturesAttributes)
+                {
+                    var ctorWithDiagnostics = fixtureAttribute.FixtureType.GetConstructor(new[] { typeof(IMessageSink) });
+                    if (ctorWithDiagnostics != null)
+                    {
+                        _assemblyFixtureMappings[fixtureAttribute.FixtureType] = Activator.CreateInstance(fixtureAttribute.FixtureType, DiagnosticMessageSink);
+                    }
+                    else
+                    {
+                        _assemblyFixtureMappings[fixtureAttribute.FixtureType] = Activator.CreateInstance(fixtureAttribute.FixtureType);
+                    }
+                }
+            });
+        }
+
+        protected override Task BeforeTestAssemblyFinishedAsync()
+        {
+            // Dispose fixtures
+            foreach (var disposable in _assemblyFixtureMappings.Values.OfType<IDisposable>())
+            {
+                Aggregator.Run(disposable.Dispose);
+            }
+
+            return base.BeforeTestAssemblyFinishedAsync();
+        }
+
+        protected override Task<RunSummary> RunTestCollectionAsync(
+            IMessageBus messageBus,
+            ITestCollection testCollection,
+            IEnumerable<IXunitTestCase> testCases,
+            CancellationTokenSource cancellationTokenSource)
+            => new AspNetTestCollectionRunner(
+                _assemblyFixtureMappings,
+                testCollection,
+                testCases,
+                DiagnosticMessageSink,
+                messageBus,
+                TestCaseOrderer,
+                new ExceptionAggregator(Aggregator),
+                cancellationTokenSource).RunAsync();
+    }
+}

src/Testing/src/xunit/AspNetTestCaseRunner.cs

@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Threading;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    internal class AspNetTestCaseRunner : XunitTestCaseRunner
+    {
+        public AspNetTestCaseRunner(
+            IXunitTestCase testCase,
+            string displayName,
+            string skipReason,
+            object[] constructorArguments,
+            object[] testMethodArguments,
+            IMessageBus messageBus,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource)
+            : base(testCase, displayName, skipReason, constructorArguments, testMethodArguments, messageBus, aggregator, cancellationTokenSource)
+        {
+        }
+
+        protected override XunitTestRunner CreateTestRunner(ITest test, IMessageBus messageBus, Type testClass, object[] constructorArguments, MethodInfo testMethod, object[] testMethodArguments, string skipReason, IReadOnlyList<BeforeAfterTestAttribute> beforeAfterAttributes, ExceptionAggregator aggregator, CancellationTokenSource cancellationTokenSource)
+        {
+            return new AspNetTestRunner(test, messageBus, testClass, constructorArguments, testMethod, testMethodArguments, skipReason, beforeAfterAttributes, aggregator, cancellationTokenSource);
+        }
+    }
+}

src/Testing/src/xunit/AspNetTestClassRunner.cs

@@ -0,0 +1,44 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    internal class AspNetTestClassRunner : XunitTestClassRunner
+    {
+        public AspNetTestClassRunner(
+            ITestClass testClass,
+            IReflectionTypeInfo @class,
+            IEnumerable<IXunitTestCase> testCases,
+            IMessageSink diagnosticMessageSink,
+            IMessageBus messageBus,
+            ITestCaseOrderer testCaseOrderer,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource,
+            IDictionary<Type, object> collectionFixtureMappings)
+            : base(testClass, @class, testCases, diagnosticMessageSink, messageBus, testCaseOrderer, aggregator, cancellationTokenSource, collectionFixtureMappings)
+        {
+        }
+
+        protected override Task<RunSummary> RunTestMethodAsync(ITestMethod testMethod, IReflectionMethodInfo method, IEnumerable<IXunitTestCase> testCases, object[] constructorArguments)
+        {
+            var runner = new AspNetTestMethodRunner(
+                testMethod,
+                Class,
+                method,
+                testCases,
+                DiagnosticMessageSink,
+                MessageBus,
+                new ExceptionAggregator(Aggregator),
+                CancellationTokenSource,
+                constructorArguments);
+            return runner.RunAsync();
+        }
+    }
+}

src/Testing/src/xunit/AspNetTestCollectionRunner.cs

@@ -0,0 +1,75 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class AspNetTestCollectionRunner : XunitTestCollectionRunner
+    {
+        private readonly IDictionary<Type, object> _assemblyFixtureMappings;
+        private readonly IMessageSink _diagnosticMessageSink;
+
+        public AspNetTestCollectionRunner(
+            Dictionary<Type, object> assemblyFixtureMappings,
+            ITestCollection testCollection,
+            IEnumerable<IXunitTestCase> testCases,
+            IMessageSink diagnosticMessageSink,
+            IMessageBus messageBus,
+            ITestCaseOrderer testCaseOrderer,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource)
+            : base(testCollection, testCases, diagnosticMessageSink, messageBus, testCaseOrderer, aggregator, cancellationTokenSource)
+        {
+            _assemblyFixtureMappings = assemblyFixtureMappings;
+            _diagnosticMessageSink = diagnosticMessageSink;
+        }
+
+        protected override async Task AfterTestCollectionStartingAsync()
+        {
+            await base.AfterTestCollectionStartingAsync();
+
+            // note: We pass the assembly fixtures into the runner as ICollectionFixture<> - this seems to work OK without any
+            // drawbacks. It's reasonable that we could add IAssemblyFixture<> and related plumbing if it ever became required.
+            //
+            // The reason for assembly fixture is when we want to start/stop something as the project scope - tests can only be
+            // in one test collection at a time.
+            foreach (var mapping in _assemblyFixtureMappings)
+            {
+                CollectionFixtureMappings.Add(mapping.Key, mapping.Value);
+            }
+        }
+
+        protected override Task BeforeTestCollectionFinishedAsync()
+        {
+            // We need to remove the assembly fixtures so they won't get disposed.
+            foreach (var mapping in _assemblyFixtureMappings)
+            {
+                CollectionFixtureMappings.Remove(mapping.Key);
+            }
+
+            return base.BeforeTestCollectionFinishedAsync();
+        }
+
+        protected override Task<RunSummary> RunTestClassAsync(ITestClass testClass, IReflectionTypeInfo @class, IEnumerable<IXunitTestCase> testCases)
+        {
+            var runner = new AspNetTestClassRunner(
+                testClass,
+                @class,
+                testCases,
+                DiagnosticMessageSink,
+                MessageBus,
+                TestCaseOrderer,
+                new ExceptionAggregator(Aggregator),
+                CancellationTokenSource,
+                CollectionFixtureMappings);
+            return runner.RunAsync();
+        }
+    }
+}

src/Testing/src/xunit/AspNetTestFramework.cs

@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Reflection;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class AspNetTestFramework : XunitTestFramework
+    {
+        public AspNetTestFramework(IMessageSink messageSink)
+            : base(messageSink)
+        {
+        }
+
+        protected override ITestFrameworkExecutor CreateExecutor(AssemblyName assemblyName)
+            => new AspNetTestFrameworkExecutor(assemblyName, SourceInformationProvider, DiagnosticMessageSink);
+    }
+}

src/Testing/src/xunit/AspNetTestFrameworkExecutor.cs

@@ -0,0 +1,26 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Reflection;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class AspNetTestFrameworkExecutor : XunitTestFrameworkExecutor
+    {
+        public AspNetTestFrameworkExecutor(AssemblyName assemblyName, ISourceInformationProvider sourceInformationProvider, IMessageSink diagnosticMessageSink)
+            : base(assemblyName, sourceInformationProvider, diagnosticMessageSink)
+        {
+        }
+
+        protected override async void RunTestCases(IEnumerable<IXunitTestCase> testCases, IMessageSink executionMessageSink, ITestFrameworkExecutionOptions executionOptions)
+        {
+            using (var assemblyRunner = new AspNetTestAssemblyRunner(TestAssembly, testCases, DiagnosticMessageSink, executionMessageSink, executionOptions))
+            {
+                await assemblyRunner.RunAsync();
+            }
+        }
+    }
+}

src/Testing/src/xunit/AspNetTestInvoker.cs

@@ -0,0 +1,84 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    internal class AspNetTestInvoker : XunitTestInvoker
+    {
+        public AspNetTestInvoker(
+            ITest test,
+            IMessageBus messageBus,
+            Type testClass,
+            object[] constructorArguments,
+            MethodInfo testMethod,
+            object[] testMethodArguments,
+            IReadOnlyList<BeforeAfterTestAttribute> beforeAfterAttributes,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource)
+            : base(test, messageBus, testClass, constructorArguments, testMethod, testMethodArguments, beforeAfterAttributes, aggregator, cancellationTokenSource)
+        {
+        }
+
+        protected override async Task<decimal> InvokeTestMethodAsync(object testClassInstance)
+        {
+            var output = new TestOutputHelper();
+            output.Initialize(MessageBus, Test);
+
+            var context = new TestContext(TestClass, ConstructorArguments, TestMethod, TestMethodArguments, output);
+            var lifecycleHooks = GetLifecycleHooks(testClassInstance, TestClass, TestMethod);
+
+            await Aggregator.RunAsync(async () =>
+            {
+                foreach (var lifecycleHook in lifecycleHooks)
+                {
+                    await lifecycleHook.OnTestStartAsync(context, CancellationTokenSource.Token);
+                }
+            });
+
+            var time = await base.InvokeTestMethodAsync(testClassInstance);
+
+            await Aggregator.RunAsync(async () =>
+            {
+                var exception = Aggregator.HasExceptions ? Aggregator.ToException() : null;
+                foreach (var lifecycleHook in lifecycleHooks)
+                {
+                    await lifecycleHook.OnTestEndAsync(context, exception, CancellationTokenSource.Token);
+                }
+            });
+
+            return time;
+        }
+
+        private static IEnumerable<ITestMethodLifecycle> GetLifecycleHooks(object testClassInstance, Type testClass, MethodInfo testMethod)
+        {
+            foreach (var attribute in testMethod.GetCustomAttributes(inherit: true).OfType<ITestMethodLifecycle>())
+            {
+                yield return attribute;
+            }
+
+            if (testClassInstance is ITestMethodLifecycle instance)
+            {
+                yield return instance;
+            }
+
+            foreach (var attribute in testClass.GetCustomAttributes(inherit: true).OfType<ITestMethodLifecycle>())
+            {
+                yield return attribute;
+            }
+
+            foreach (var attribute in testClass.Assembly.GetCustomAttributes(inherit: true).OfType<ITestMethodLifecycle>())
+            {
+                yield return attribute;
+            }
+        }
+    }
+}

src/Testing/src/xunit/AspNetTestMethodRunner.cs

@@ -0,0 +1,73 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Testing.xunit;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    internal class AspNetTestMethodRunner : XunitTestMethodRunner
+    {
+        private readonly object[] _constructorArguments;
+        private readonly IMessageSink _diagnosticMessageSink;
+
+        public AspNetTestMethodRunner(
+            ITestMethod testMethod,
+            IReflectionTypeInfo @class,
+            IReflectionMethodInfo method,
+            IEnumerable<IXunitTestCase> testCases,
+            IMessageSink diagnosticMessageSink,
+            IMessageBus messageBus,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource,
+            object[] constructorArguments)
+            : base(testMethod, @class, method, testCases, diagnosticMessageSink, messageBus, aggregator, cancellationTokenSource, constructorArguments)
+        {
+            _diagnosticMessageSink = diagnosticMessageSink;
+            _constructorArguments = constructorArguments;
+        }
+
+        protected override Task<RunSummary> RunTestCaseAsync(IXunitTestCase testCase)
+        {
+            if (testCase.GetType() == typeof(XunitTestCase))
+            {
+                // If we get here this is a 'regular' test case, not something that represents a skipped test.
+                //
+                // We can take control of it's invocation thusly.
+                var runner = new AspNetTestCaseRunner(
+                    testCase,
+                    testCase.DisplayName,
+                    testCase.SkipReason,
+                    _constructorArguments,
+                    testCase.TestMethodArguments,
+                    MessageBus,
+                    new ExceptionAggregator(Aggregator),
+                    CancellationTokenSource);
+                return runner.RunAsync();
+            }
+
+            if (testCase.GetType() == typeof(XunitTheoryTestCase))
+            {
+                // If we get here this is a 'regular' theory test case, not something that represents a skipped test.
+                //
+                // We can take control of it's invocation thusly.
+                var runner = new AspNetTheoryTestCaseRunner(
+                    testCase,
+                    testCase.DisplayName,
+                    testCase.SkipReason,
+                    _constructorArguments,
+                    _diagnosticMessageSink,
+                    MessageBus,
+                    new ExceptionAggregator(Aggregator),
+                    CancellationTokenSource);
+                return runner.RunAsync();
+            }
+
+            return base.RunTestCaseAsync(testCase);
+        }
+    }
+}

src/Testing/src/xunit/AspNetTestRunner.cs

@@ -0,0 +1,78 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    internal class AspNetTestRunner : XunitTestRunner
+    {
+        public AspNetTestRunner(
+            ITest test,
+            IMessageBus messageBus,
+            Type testClass,
+            object[] constructorArguments,
+            MethodInfo testMethod,
+            object[] testMethodArguments,
+            string skipReason,
+            IReadOnlyList<BeforeAfterTestAttribute> beforeAfterAttributes,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource)
+            : base(test, messageBus, testClass, constructorArguments, testMethod, testMethodArguments, skipReason, beforeAfterAttributes, aggregator, cancellationTokenSource)
+        {
+        }
+
+        protected override async Task<decimal> InvokeTestMethodAsync(ExceptionAggregator aggregator)
+        {
+            var repeatAttribute = GetRepeatAttribute(TestMethod);
+            if (repeatAttribute == null)
+            {
+                return await InvokeTestMethodCoreAsync(aggregator);
+            }
+
+            var repeatContext = new RepeatContext(repeatAttribute.RunCount);
+            RepeatContext.Current = repeatContext;
+
+            var timeTaken = 0.0M;
+            for (repeatContext.CurrentIteration = 0; repeatContext.CurrentIteration < repeatContext.Limit; repeatContext.CurrentIteration++)
+            {
+                timeTaken = await InvokeTestMethodCoreAsync(aggregator);
+                if (aggregator.HasExceptions)
+                {
+                    return timeTaken;
+                }
+            }
+
+            return timeTaken;
+        }
+
+        private Task<decimal> InvokeTestMethodCoreAsync(ExceptionAggregator aggregator)
+        {
+            var invoker = new AspNetTestInvoker(Test, MessageBus, TestClass, ConstructorArguments, TestMethod, TestMethodArguments, BeforeAfterAttributes, aggregator, CancellationTokenSource);
+            return invoker.RunAsync();
+        }
+
+        private RepeatAttribute GetRepeatAttribute(MethodInfo methodInfo)
+        {
+            var attributeCandidate = methodInfo.GetCustomAttribute<RepeatAttribute>();
+            if (attributeCandidate != null)
+            {
+                return attributeCandidate;
+            }
+
+            attributeCandidate = methodInfo.DeclaringType.GetCustomAttribute<RepeatAttribute>();
+            if (attributeCandidate != null)
+            {
+                return attributeCandidate;
+            }
+
+            return methodInfo.DeclaringType.Assembly.GetCustomAttribute<RepeatAttribute>();
+        }
+    }
+}

src/Testing/src/xunit/AspNetTheoryTestCaseRunner.cs

@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Threading;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing.xunit
+{
+    internal class AspNetTheoryTestCaseRunner : XunitTheoryTestCaseRunner
+    {
+        public AspNetTheoryTestCaseRunner(
+            IXunitTestCase testCase,
+            string displayName,
+            string skipReason,
+            object[] constructorArguments,
+            IMessageSink diagnosticMessageSink,
+            IMessageBus messageBus,
+            ExceptionAggregator aggregator,
+            CancellationTokenSource cancellationTokenSource)
+            : base(testCase, displayName, skipReason, constructorArguments, diagnosticMessageSink, messageBus, aggregator, cancellationTokenSource)
+        {
+        }
+
+        protected override XunitTestRunner CreateTestRunner(ITest test, IMessageBus messageBus, Type testClass, object[] constructorArguments, MethodInfo testMethod, object[] testMethodArguments, string skipReason, IReadOnlyList<BeforeAfterTestAttribute> beforeAfterAttributes, ExceptionAggregator aggregator, CancellationTokenSource cancellationTokenSource)
+        {
+            return new AspNetTestRunner(test, messageBus, testClass, constructorArguments, testMethod, testMethodArguments, skipReason, beforeAfterAttributes, aggregator, cancellationTokenSource);
+        }
+    }
+}

src/Testing/src/xunit/AssemblyFixtureAttribute.cs

@@ -0,0 +1,18 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
+    public class AssemblyFixtureAttribute : Attribute
+    {
+        public AssemblyFixtureAttribute(Type fixtureType)
+        {
+            FixtureType = fixtureType;
+        }
+
+        public Type FixtureType { get; private set; }
+    }
+}

src/Testing/src/xunit/ConditionalTheoryDiscoverer.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using Xunit.Abstractions;
 using Xunit.Sdk;
@@ -63,5 +64,24 @@ namespace Microsoft.AspNetCore.Testing
                 base.CreateTestCasesForSkippedDataRow(discoveryOptions, testMethod, theoryAttribute, dataRow, skipReason)
                 : base.CreateTestCasesForDataRow(discoveryOptions, testMethod, theoryAttribute, dataRow);
         }
+
+        protected override IEnumerable<IXunitTestCase> CreateTestCasesForSkippedDataRow(
+            ITestFrameworkDiscoveryOptions discoveryOptions,
+            ITestMethod testMethod,
+            IAttributeInfo theoryAttribute,
+            object[] dataRow,
+            string skipReason)
+        {
+            return new[]
+            {
+                new WORKAROUND_SkippedDataRowTestCase(DiagnosticMessageSink, discoveryOptions.MethodDisplayOrDefault(), discoveryOptions.MethodDisplayOptionsOrDefault(), testMethod, skipReason, dataRow),
+            };
+        }
+
+        [Obsolete]
+        protected override IXunitTestCase CreateTestCaseForSkippedDataRow(ITestFrameworkDiscoveryOptions discoveryOptions, ITestMethod testMethod, IAttributeInfo theoryAttribute, object[] dataRow, string skipReason)
+        {
+            return new WORKAROUND_SkippedDataRowTestCase(DiagnosticMessageSink, discoveryOptions.MethodDisplayOrDefault(), discoveryOptions.MethodDisplayOptionsOrDefault(), testMethod, skipReason, dataRow);
+        }
     }
 }

src/Testing/src/xunit/FlakyAttribute.cs

@@ -49,7 +49,7 @@ namespace Microsoft.AspNetCore.Testing
     /// to <c>xunit.console.exe</c>. Similarly, it can run only flaky tests using <c>-trait "Flaky:AzP:OS:all=true" -trait "Flaky:AzP:OS:Darwin=true"</c>
     /// </para>
     /// </example>
-    [TraitDiscoverer("Microsoft.AspNetCore.Testing." + nameof(FlakyTestDiscoverer), "Microsoft.AspNetCore.Testing")]
+    [TraitDiscoverer("Microsoft.AspNetCore.Testing." + nameof(FlakyTraitDiscoverer), "Microsoft.AspNetCore.Testing")]
     [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class | AttributeTargets.Assembly)]
     public sealed class FlakyAttribute : Attribute, ITraitAttribute
     {

src/Testing/src/xunit/FlakyTraitDiscoverer.cs

@@ -6,7 +6,7 @@ using Xunit.Sdk;
 // Do not change this namespace without changing the usage in FlakyAttribute
 namespace Microsoft.AspNetCore.Testing
 {
-    public class FlakyTestDiscoverer : ITraitDiscoverer
+    public class FlakyTraitDiscoverer : ITraitDiscoverer
     {
         public IEnumerable<KeyValuePair<string, string>> GetTraits(IAttributeInfo traitAttribute)
         {

src/Testing/src/xunit/SkippedTestCase.cs

@@ -2,6 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Threading;
+using System.Threading.Tasks;
 using Xunit.Abstractions;
 using Xunit.Sdk;
 
@@ -33,8 +35,11 @@ namespace Microsoft.AspNetCore.Testing
 
         public override void Deserialize(IXunitSerializationInfo data)
         {
-            base.Deserialize(data);
             _skipReason = data.GetValue<string>(nameof(_skipReason));
+
+            // We need to call base after reading our value, because Deserialize will call
+            // into GetSkipReason.
+            base.Deserialize(data);
         }
 
         public override void Serialize(IXunitSerializationInfo data)

src/Testing/src/xunit/WORKAROUND_SkippedDataRowTestCase.cs

@@ -0,0 +1,80 @@
+using System;
+using System.ComponentModel;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    // This is a workaround for https://github.com/xunit/xunit/issues/1782 - as such, this code is a copy-paste
+    // from xUnit with the exception of fixing the bug.
+    //
+    // This will only work with [ConditionalTheory].
+    internal class WORKAROUND_SkippedDataRowTestCase : XunitTestCase
+    {
+        string skipReason;
+
+        /// <summary/>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        [Obsolete("Called by the de-serializer; should only be called by deriving classes for de-serialization purposes")]
+        public WORKAROUND_SkippedDataRowTestCase() { }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XunitSkippedDataRowTestCase"/> class.
+        /// </summary>
+        /// <param name="diagnosticMessageSink">The message sink used to send diagnostic messages</param>
+        /// <param name="defaultMethodDisplay">Default method display to use (when not customized).</param>
+        /// <param name="testMethod">The test method this test case belongs to.</param>
+        /// <param name="skipReason">The reason that this test case will be skipped</param>
+        /// <param name="testMethodArguments">The arguments for the test method.</param>
+        [Obsolete("Please call the constructor which takes TestMethodDisplayOptions")]
+        public WORKAROUND_SkippedDataRowTestCase(IMessageSink diagnosticMessageSink,
+                                           TestMethodDisplay defaultMethodDisplay,
+                                           ITestMethod testMethod,
+                                           string skipReason,
+                                           object[] testMethodArguments = null)
+            : this(diagnosticMessageSink, defaultMethodDisplay, TestMethodDisplayOptions.None, testMethod, skipReason, testMethodArguments) { }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XunitSkippedDataRowTestCase"/> class.
+        /// </summary>
+        /// <param name="diagnosticMessageSink">The message sink used to send diagnostic messages</param>
+        /// <param name="defaultMethodDisplay">Default method display to use (when not customized).</param>
+        /// <param name="defaultMethodDisplayOptions">Default method display options to use (when not customized).</param>
+        /// <param name="testMethod">The test method this test case belongs to.</param>
+        /// <param name="skipReason">The reason that this test case will be skipped</param>
+        /// <param name="testMethodArguments">The arguments for the test method.</param>
+        public WORKAROUND_SkippedDataRowTestCase(IMessageSink diagnosticMessageSink,
+                                           TestMethodDisplay defaultMethodDisplay,
+                                           TestMethodDisplayOptions defaultMethodDisplayOptions,
+                                           ITestMethod testMethod,
+                                           string skipReason,
+                                           object[] testMethodArguments = null)
+            : base(diagnosticMessageSink, defaultMethodDisplay, defaultMethodDisplayOptions, testMethod, testMethodArguments)
+        {
+            this.skipReason = skipReason;
+        }
+
+        /// <inheritdoc/>
+        public override void Deserialize(IXunitSerializationInfo data)
+        {
+            // SkipReason has to be read before we call base.Deserialize, this is the workaround.
+            this.skipReason = data.GetValue<string>("SkipReason");
+
+            base.Deserialize(data);
+        }
+
+        /// <inheritdoc/>
+        protected override string GetSkipReason(IAttributeInfo factAttribute)
+        {
+            return skipReason;
+        }
+
+        /// <inheritdoc/>
+        public override void Serialize(IXunitSerializationInfo data)
+        {
+            base.Serialize(data);
+
+            data.AddValue("SkipReason", skipReason);
+        }
+    }
+}

src/Testing/test/AssemblyFixtureTest.cs

@@ -0,0 +1,47 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Xunit;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    // We include a collection and assembly fixture to verify that they both still work.
+    [Collection("MyCollection")]
+    [TestCaseOrderer("Microsoft.AspNetCore.Testing.AlphabeticalOrderer", "Microsoft.AspNetCore.Testing.Tests")]
+    public class AssemblyFixtureTest
+    {
+        public AssemblyFixtureTest(TestAssemblyFixture assemblyFixture, TestCollectionFixture collectionFixture)
+        {
+            AssemblyFixture = assemblyFixture;
+            CollectionFixture = collectionFixture;
+        }
+
+        public TestAssemblyFixture AssemblyFixture { get; }
+        public TestCollectionFixture CollectionFixture { get; }
+
+        [Fact]
+        public void A()
+        {
+            Assert.NotNull(AssemblyFixture);
+            Assert.Equal(0, AssemblyFixture.Count);
+
+            Assert.NotNull(CollectionFixture);
+            Assert.Equal(0, CollectionFixture.Count);
+
+            AssemblyFixture.Count++;
+            CollectionFixture.Count++;
+        }
+
+        [Fact]
+        public void B()
+        {
+            Assert.Equal(1, AssemblyFixture.Count);
+            Assert.Equal(1, CollectionFixture.Count);
+        }
+    }
+
+    [CollectionDefinition("MyCollection", DisableParallelization = true)]
+    public class MyCollection : ICollectionFixture<TestCollectionFixture>
+    {
+    }
+}

src/Testing/test/ConditionalFactTest.cs

@@ -29,7 +29,7 @@ namespace Microsoft.AspNetCore.Testing
             Assert.True(false, "This test should always be skipped.");
         }
 
-#if NETCOREAPP3_0
+#if NETCOREAPP
         [ConditionalFact]
         [FrameworkSkipCondition(RuntimeFrameworks.CLR)]
         public void ThisTestMustRunOnCoreCLR()

src/Testing/test/ConditionalTheoryTest.cs

@@ -81,7 +81,7 @@ namespace Microsoft.AspNetCore.Testing
             Assert.True(true);
         }
 
-#if NETCOREAPP3_0
+#if NETCOREAPP
         [ConditionalTheory]
         [FrameworkSkipCondition(RuntimeFrameworks.CLR)]
         [MemberData(nameof(GetInts))]

src/Testing/test/Microsoft.AspNetCore.Testing.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
 
     <!-- allow skipped tests -->
     <NoWarn>$(NoWarn);xUnit1004</NoWarn>

src/Testing/test/Properties/AssemblyInfo.cs

@@ -0,0 +1,6 @@
+using Microsoft.AspNetCore.Testing;
+using Xunit;
+
+[assembly: Repeat(1)]
+[assembly: AssemblyFixture(typeof(TestAssemblyFixture))]
+[assembly: TestFramework("Microsoft.AspNetCore.Testing.AspNetTestFramework", "Microsoft.AspNetCore.Testing")]

src/Testing/test/RepeatTest.cs

@@ -0,0 +1,43 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Xunit;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    [Repeat]
+    public class RepeatTest
+    {
+        public static int _runCount = 0;
+
+        [Fact]
+        [Repeat(5)]
+        public void RepeatLimitIsSetCorrectly()
+        {
+            Assert.Equal(5, RepeatContext.Current.Limit);
+        }
+
+        [Fact]
+        [Repeat(5)]
+        public void RepeatRunsTestSpecifiedNumberOfTimes()
+        {
+            Assert.Equal(RepeatContext.Current.CurrentIteration, _runCount);
+            _runCount++;
+        }
+
+        [Fact]
+        public void RepeatCanBeSetOnClass()
+        {
+            Assert.Equal(10, RepeatContext.Current.Limit);
+        }
+    }
+
+    public class LoggedTestXunitRepeatAssemblyTests
+    {
+        [Fact]
+        public void RepeatCanBeSetOnAssembly()
+        {
+            Assert.Equal(1, RepeatContext.Current.Limit);
+        }
+    }
+}

src/Testing/test/TestAssemblyFixture.cs

@@ -0,0 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class TestAssemblyFixture
+    {
+        public int Count { get; set; }
+    }
+}

src/Testing/test/TestCollectionFixture.cs

@@ -0,0 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class TestCollectionFixture
+    {
+        public int Count { get; set; }
+    }
+}

src/Testing/test/TestContextTest.cs

@@ -0,0 +1,83 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Testing
+{
+    public class TestContextTest : ITestMethodLifecycle
+    {
+        public TestContext Context { get; private set; }
+
+        [Fact]
+        public void FullName_IsUsed_ByDefault()
+        {
+            Assert.Equal(GetType().FullName, Context.FileOutput.TestClassName);
+        }
+
+        Task ITestMethodLifecycle.OnTestStartAsync(TestContext context, CancellationToken cancellationToken)
+        {
+            Context = context;
+            return Task.CompletedTask;
+        }
+
+        Task ITestMethodLifecycle.OnTestEndAsync(TestContext context, Exception exception, CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}
+
+namespace Microsoft.AspNetCore.Testing.Tests
+{
+    public class TestContextNameShorteningTest : ITestMethodLifecycle
+    {
+        public TestContext Context { get; private set; }
+
+        [Fact]
+        public void NameIsShortenedWhenAssemblyNameIsAPrefix()
+        {
+            Assert.Equal(GetType().Name, Context.FileOutput.TestClassName);
+        }
+
+        Task ITestMethodLifecycle.OnTestStartAsync(TestContext context, CancellationToken cancellationToken)
+        {
+            Context = context;
+            return Task.CompletedTask;
+        }
+
+        Task ITestMethodLifecycle.OnTestEndAsync(TestContext context, Exception exception, CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}
+
+namespace Microsoft.AspNetCore.Testing
+{
+    [ShortClassName]
+    public class TestContextTestClassShortNameAttributeTest : ITestMethodLifecycle
+    {
+        public TestContext Context { get; private set; }
+
+        [Fact]
+        public void ShortClassNameUsedWhenShortClassNameAttributeSpecified()
+        {
+            Assert.Equal(GetType().Name, Context.FileOutput.TestClassName);
+        }
+
+        Task ITestMethodLifecycle.OnTestStartAsync(TestContext context, CancellationToken cancellationToken)
+        {
+            Context = context;
+            return Task.CompletedTask;
+        }
+
+        Task ITestMethodLifecycle.OnTestEndAsync(TestContext context, Exception exception, CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}

src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.csproj

@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.WebEncoders.netstandard2.0.cs" />
@@ -9,8 +9,8 @@
     <Reference Include="Microsoft.Extensions.Options"  />
     <Reference Include="System.Text.Encodings.Web"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
-    <Compile Include="Microsoft.Extensions.WebEncoders.netcoreapp3.0.cs" />
+    <Compile Include="Microsoft.Extensions.WebEncoders.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
   </ItemGroup>

src/WebEncoders/src/Microsoft.Extensions.WebEncoders.csproj

@@ -2,8 +2,8 @@
 
   <PropertyGroup>
     <Description>Contains registration and configuration APIs to add the core framework encoders to a dependency injection container.</Description>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
-    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore</PackageTags>

src/WebEncoders/test/Microsoft.Extensions.WebEncoders.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;net472</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>