From 49f206c272f542019e8fb436e2910ec7b60b24f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Amaury=20Lev=C3=A9?= <amauryleve@microsoft.com>
Date: Sat, 13 Jun 2026 01:44:12 +0200
Subject: [PATCH] test: add DataTestMethod edge cases for
 TypeContainingTestMethodShouldBeATestClassAnalyzer (MSTEST0030)
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Two new test cases verifying that DataTestMethodAttribute (which inherits
TestMethodAttribute) is correctly recognized by the Inherits() check:

1. WhenNonTestClassHasDataTestMethod_Diagnostic – a non-test class with a
   [DataTestMethod] directly triggers the diagnostic and the fixer adds [TestClass].

2. WhenNonTestClassInheritsDataTestMethodFromAbstractBase_Diagnostic – the
   inheritance walk correctly detects DataTestMethod from an abstract base class,
   firing the diagnostic only on the concrete derived class (abstract base is
   exempt per the IsAbstract guard).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 ...stMethodShouldBeATestClassAnalyzerTests.cs | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/test/UnitTests/MSTest.Analyzers.UnitTests/TypeContainingTestMethodShouldBeATestClassAnalyzerTests.cs b/test/UnitTests/MSTest.Analyzers.UnitTests/TypeContainingTestMethodShouldBeATestClassAnalyzerTests.cs
index bec343fbaf..ae719e5983 100644
--- a/test/UnitTests/MSTest.Analyzers.UnitTests/TypeContainingTestMethodShouldBeATestClassAnalyzerTests.cs
+++ b/test/UnitTests/MSTest.Analyzers.UnitTests/TypeContainingTestMethodShouldBeATestClassAnalyzerTests.cs
@@ -462,4 +462,72 @@ public void TestMethod1()
 
         await VerifyCS.VerifyCodeFixAsync(code, fixedCode);
     }
+
+    [TestMethod]
+    public async Task WhenNonTestClassHasDataTestMethod_Diagnostic()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            public class [|MyTestClass|]
+            {
+                [DataTestMethod]
+                [DataRow(1)]
+                public void TestMethod1(int value) {}
+            }
+            """;
+
+        string fixedCode = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            [TestClass]
+            public class MyTestClass
+            {
+                [DataTestMethod]
+                [DataRow(1)]
+                public void TestMethod1(int value) {}
+            }
+            """;
+
+        await VerifyCS.VerifyCodeFixAsync(code, fixedCode);
+    }
+
+    [TestMethod]
+    public async Task WhenNonTestClassInheritsDataTestMethodFromAbstractBase_Diagnostic()
+    {
+        // Abstract base is exempt from the diagnostic; derived non-test class
+        // that inherits [DataTestMethod] via the inheritance walk should fire.
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            public abstract class AbstractBase
+            {
+                [DataTestMethod]
+                [DataRow(1)]
+                public void TestMethod1(int value) {}
+            }
+
+            public class [|MyTestClass|] : AbstractBase
+            {
+            }
+            """;
+
+        string fixedCode = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            public abstract class AbstractBase
+            {
+                [DataTestMethod]
+                [DataRow(1)]
+                public void TestMethod1(int value) {}
+            }
+
+            [TestClass]
+            public class MyTestClass : AbstractBase
+            {
+            }
+            """;
+
+        await VerifyCS.VerifyCodeFixAsync(code, fixedCode);
+    }
 }