MSTEST0029 do not report on implementation of interface (#4803)

microsoft · Jan 28, 2025 · f492095 · f492095
1 parent 3c7787e
commit f492095
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Showing 3 changed files with 132 additions and 1 deletion.
diff --git a/src/Analyzers/MSTest.Analyzers/PublicMethodShouldBeTestMethodAnalyzer.cs b/src/Analyzers/MSTest.Analyzers/PublicMethodShouldBeTestMethodAnalyzer.cs
@@ -64,7 +64,9 @@ private static void AnalyzeSymbol(SymbolAnalysisContext context, INamedTypeSymbo
             return;
         }
 
-        if (!methodSymbol.HasValidTestMethodSignature(taskSymbol, valueTaskSymbol, canDiscoverInternals))
+        if (!methodSymbol.HasValidTestMethodSignature(taskSymbol, valueTaskSymbol, canDiscoverInternals)
+            || methodSymbol.IsVirtual
+            || methodSymbol.IsOverride)
         {
             return;
         }
@@ -85,6 +87,13 @@ private static void AnalyzeSymbol(SymbolAnalysisContext context, INamedTypeSymbo
             return;
         }
 
+        // We consider that if the method implements an interface member, it is not a test method.
+        // Explicit implementations are not public so they are discarded earlier.
+        if (methodSymbol.IsImplementationOfAnyInterfaceMember())
+        {
+            return;
+        }
+
         ImmutableArray<AttributeData> methodAttributes = methodSymbol.GetAttributes();
         // check if the method has testMethod, testInitialize or testCleanup attribute
         bool hasValidAttribute = false;

diff --git a/src/Analyzers/MSTest.Analyzers/RoslynAnalyzerHelpers/IMethodSymbolExtensions.cs b/src/Analyzers/MSTest.Analyzers/RoslynAnalyzerHelpers/IMethodSymbolExtensions.cs
@@ -10,6 +10,38 @@ namespace Analyzer.Utilities.Extensions;
 
 internal static class IMethodSymbolExtensions
 {
+    public static bool IsImplementationOfAnyInterfaceMember(this ISymbol symbol)
+        => IsImplementationOfAnyInterfaceMember<ISymbol>(symbol);
+
+    /// <summary>
+    /// Checks if a given symbol implements an interface member implicitly
+    /// </summary>
+    public static bool IsImplementationOfAnyInterfaceMember<TSymbol>(this ISymbol symbol)
+        where TSymbol : ISymbol
+    {
+        if (symbol.ContainingType == null)
+        {
+            return false;
+        }
+
+        foreach (INamedTypeSymbol interfaceSymbol in symbol.ContainingType.AllInterfaces)
+        {
+            foreach (TSymbol interfaceMember in interfaceSymbol.GetMembers().OfType<TSymbol>())
+            {
+                if (IsImplementationOfInterfaceMember(symbol, interfaceMember))
+                {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    public static bool IsImplementationOfInterfaceMember(this ISymbol symbol, [NotNullWhen(returnValue: true)] ISymbol? interfaceMember)
+        => interfaceMember != null
+        && SymbolEqualityComparer.Default.Equals(symbol, symbol.ContainingType.FindImplementationForInterfaceMember(interfaceMember));
+
     /// <summary>
     /// Checks if the given method is an implementation of the given interface method
     /// Substituted with the given typeargument.

diff --git a/test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs b/test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs
@@ -252,4 +252,94 @@ public void TestCleanup()
             """;
         await VerifyCS.VerifyCodeFixAsync(code, code);
     }
+
+    [TestMethod]
+    public async Task WhenMethodIsPublicAndImplementsDispose_NoDiagnostic()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+            using System;
+
+            [TestClass]
+            public class MyTestClass : IDisposable
+            {
+                public void Dispose()
+                {
+                }
+            }
+            """;
+        await VerifyCS.VerifyAnalyzerAsync(code);
+    }
+
+    [TestMethod]
+    public async Task WhenMethodIsPublicAndImplementsUserDefinedInterface_NoDiagnostic()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+            using System;
+
+            public interface IMyInterface
+            {
+                void MyMethod();
+            }
+
+            [TestClass]
+            public class MyTestClass : IMyInterface
+            {
+                public void MyMethod()
+                {
+                }
+            }
+            """;
+        await VerifyCS.VerifyAnalyzerAsync(code);
+    }
+
+    [TestMethod]
+    public async Task WhenMethodIsPublicAndImplementsExplicitlyUserDefinedInterface_NoDiagnostic()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+            using System;
+
+            public interface IMyInterface
+            {
+                void MyMethod();
+            }
+
+            [TestClass]
+            public class MyTestClass : IMyInterface
+            {
+                void IMyInterface.MyMethod()
+                {
+                }
+            }
+            """;
+        await VerifyCS.VerifyAnalyzerAsync(code);
+    }
+
+    [TestMethod]
+    public async Task WhenMethodIsPublicAndImplementsDisposeAsVirtual_NoDiagnostic()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+            using System;
+
+            [TestClass]
+            public class MyTestClass : IDisposable
+            {
+                public virtual void Dispose()
+                {
+                }
+            }
+
+            [TestClass]
+            public class SubTestClass : MyTestClass
+            {
+                public override void Dispose()
+                {
+                }
+            }
+            """;
+        await VerifyCS.VerifyAnalyzerAsync(code);
+    }
 }