xunit/xunit#2978: Add a diagnostic suppressor for VSTHRD200

src/xunit.analyzers.tests/Suppressors/UseAsyncSuffixForAsyncMethodsSuppressorTests.cs

@@ -0,0 +1,38 @@
+#if NETCOREAPP  // System.Collections.Immutable 1.6.0 conflicts with 6.0.0 in NetFx
+
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Testing;
+using Xunit;
+using Xunit.Analyzers;
+using Verify = CSharpVerifier<Xunit.Suppressors.UseAsyncSuffixForAsyncMethodsSuppressor>;
+
+public class UseAsyncSuffixForAsyncMethodsSuppressorTests
+{
+	[Fact]
+	public async Task AcceptanceTest()
+	{
+		var code = /* lang=c#-test */ """
+			using System.Threading.Tasks;
+			using Xunit;
+
+			public class NonTestClass {
+			    public async Task {|#0:NonTestMethod|}() { }
+			}
+
+			public class TestClass {
+			    [Fact]
+			    public async Task {|#1:TestMethod|]() { }
+			}
+			""";
+		var expected = new[]
+		{
+			new DiagnosticResult("VSTHRD200", DiagnosticSeverity.Warning).WithLocation(0),
+			new DiagnosticResult("VSTHRD200", DiagnosticSeverity.Warning).WithLocation(1).WithIsSuppressed(true),
+		};
+
+		await Verify.VerifySuppressor(code, VsThreadingAnalyzers.VSTHRD200(), expected);
+	}
+}
+
+#endif

src/xunit.analyzers.tests/Utility/3rdPartyAnalyzers/VsThreadingAnalyzers.cs

@@ -0,0 +1,26 @@
+#if NETCOREAPP  // System.Collections.Immutable 1.6.0 conflicts with 6.0.0 in NetFx
+
+using System;
+using System.IO;
+using System.Reflection;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace Xunit.Analyzers;
+
+public class VsThreadingAnalyzers : AnalyzerLoaderBase
+{
+	static readonly Lazy<Assembly> assemblyVsThreading = new(LoadVsThreadingAnalyzers, isThreadSafe: true);
+	static readonly Lazy<Type> typeVSTHRD200 = new(() => FindType(assemblyVsThreading, "Microsoft.VisualStudio.Threading.Analyzers.VSTHRD200UseAsyncNamingConventionAnalyzer"), isThreadSafe: true);
+
+	public static DiagnosticAnalyzer VSTHRD200() =>
+		Activator.CreateInstance(typeVSTHRD200.Value) as DiagnosticAnalyzer ?? throw new InvalidOperationException($"Could not create instance of '{typeVSTHRD200.Value.FullName}'");
+
+	static Assembly LoadVsThreadingAnalyzers()
+	{
+		LoadAssembly(Path.Combine(NuGetPackagesFolder, "system.collections.immutable", "6.0.0", "lib", "net6.0", "System.Collections.Immutable.dll"));
+		LoadAssembly(Path.Combine(NuGetPackagesFolder, "microsoft.codeanalysis.workspaces.common", "3.11.0", "lib", "netcoreapp3.1", "Microsoft.CodeAnalysis.Workspaces.dll"));
+		return LoadAssembly(Path.Combine(NuGetPackagesFolder, "microsoft.visualstudio.threading.analyzers", "17.10.48", "analyzers", "cs", "Microsoft.VisualStudio.Threading.Analyzers.dll"));
+	}
+}
+
+#endif

src/xunit.analyzers.tests/xunit.analyzers.tests.csproj

@@ -22,6 +22,10 @@
     <!-- Download packages referenced by CodeAnalysisNetAnalyzers -->
     <PackageDownload Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="[9.0.0-preview.24216.2]" />
     <PackageDownload Include="Microsoft.CodeAnalysis.Workspaces.Common" Version="[3.11.0]" />
+
+    <!-- Download packages referenced by VsThreadingAnalyzers -->
+    <PackageDownload Include="Microsoft.VisualStudio.Threading.Analyzers" Version="[17.10.48]" />
+    <PackageDownload Include="System.Collections.Immutable" Version="[6.0.0]" Condition=" '$(TargetFramework)' == 'net8.0' " />
   </ItemGroup>
 
   <ItemGroup>

src/xunit.analyzers/Suppressors/UseAsyncSuffixForAsyncMethodsSuppressor.cs

@@ -0,0 +1,34 @@
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit.Analyzers;
+
+namespace Xunit.Suppressors;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public class UseAsyncSuffixForAsyncMethodsSuppressor : XunitDiagnosticSuppressor
+{
+	public UseAsyncSuffixForAsyncMethodsSuppressor() :
+		base(Descriptors.VSTHRD200_Suppression)
+	{ }
+
+	protected override bool ShouldSuppress(
+		Diagnostic diagnostic,
+		SuppressionAnalysisContext context,
+		XunitContext xunitContext)
+	{
+		var attributeUsageType = TypeSymbolFactory.AttributeUsageAttribute(context.Compilation);
+		if (attributeUsageType is null)
+			return false;
+
+		if (diagnostic?.Location.SourceTree is null)
+			return false;
+
+		if (diagnostic.Location.SourceTree.GetRoot().FindNode(diagnostic.Location.SourceSpan) is not MethodDeclarationSyntax methodDeclaration)
+			return false;
+
+		var semanticModel = context.GetSemanticModel(diagnostic.Location.SourceTree);
+		var methodSymbol = semanticModel.GetDeclaredSymbol(methodDeclaration) as IMethodSymbol;
+		return methodSymbol.IsTestMethod(xunitContext, attributeUsageType, strict: false);
+	}
+}

src/xunit.analyzers/Utility/CodeAnalysisExtensions.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
-using System.Runtime.CompilerServices;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Operations;
@@ -167,14 +166,16 @@ static bool IsTestClassStrict(
 	}
 
 	public static bool IsTestMethod(
-		this IMethodSymbol method,
+		this IMethodSymbol? method,
 		XunitContext xunitContext,
 		ITypeSymbol attributeUsageType,
 		bool strict)
 	{
-		Guard.ArgumentNotNull(method);
 		Guard.ArgumentNotNull(xunitContext);
 
+		if (method is null)
+			return false;
+
 		var factAttributeType = xunitContext.Core.FactAttributeType;
 		var theoryAttributeType = xunitContext.Core.TheoryAttributeType;
 		if (factAttributeType is null || theoryAttributeType is null)

src/xunit.analyzers/Utility/Descriptors.Suppressors.cs

@@ -9,4 +9,7 @@ public static partial class Descriptors
 
 	public static SuppressionDescriptor CA2007_Suppression { get; } =
 		Suppression("CA2007", "xUnit.net test methods should not call ConfigureAwait");
+
+	public static SuppressionDescriptor VSTHRD200_Suppression { get; } =
+		Suppression("VSTHRD200", "xUnit.net test methods are not directly callable and do not benefit from this naming rule");
 }