[test-improver] test: add edge case tests for TestMethodShouldNotBeIgnoredAnalyzer (MSTEST0015)

test/UnitTests/MSTest.Analyzers.UnitTests/TestMethodShouldNotBeIgnoredAnalyzerTests.cs

@@ -99,4 +99,107 @@ await VerifyCS.VerifyAnalyzerAsync(
                 .WithLocation(0)
                 .WithArguments("MyTestMethod"));
     }
+
+    [TestMethod]
+    public async Task WhenDataTestMethodIsIgnored_Diagnostic()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            [TestClass]
+            public class MyTestClass
+            {
+                [Ignore]
+                [DataTestMethod]
+                [DataRow(1)]
+                public void {|#0:MyTestMethod|}(int value)
+                {
+                }
+            }
+            """;
+
+        await VerifyCS.VerifyAnalyzerAsync(
+            code,
+            VerifyCS.Diagnostic(TestMethodShouldNotBeIgnoredAnalyzer.TestMethodShouldNotBeIgnoredRule)
+                .WithLocation(0)
+                .WithArguments("MyTestMethod"));
+    }
+
+    [TestMethod]
+    public async Task WhenMultipleTestMethodsAndOnlyOneIsIgnored_DiagnosticOnlyForIgnoredMethod()
+    {
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            [TestClass]
+            public class MyTestClass
+            {
+                [TestMethod]
+                public void NotIgnoredMethod()
+                {
+                }
+
+                [Ignore]
+                [TestMethod]
+                public void {|#0:IgnoredMethod|}()
+                {
+                }
+            }
+            """;
+
+        await VerifyCS.VerifyAnalyzerAsync(
+            code,
+            VerifyCS.Diagnostic(TestMethodShouldNotBeIgnoredAnalyzer.TestMethodShouldNotBeIgnoredRule)
+                .WithLocation(0)
+                .WithArguments("IgnoredMethod"));
+    }
+
+    [TestMethod]
+    public async Task WhenOnlyClassLevelIgnoreWithNoMethodLevelIgnore_NoDiagnostic()
+    {
+        // MSTEST0015 only checks for [Ignore] on the method itself.
+        // A class-level [Ignore] silences the whole class but is not flagged by this rule.
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            [TestClass]
+            [Ignore]
+            public class MyTestClass
+            {
+                [TestMethod]
+                public void MyTestMethod()
+                {
+                }
+            }
+            """;
+
+        await VerifyCS.VerifyAnalyzerAsync(code);
+    }
+
+    [TestMethod]
+    public async Task WhenIgnoredTestMethodHasMessage_Diagnostic()
+    {
+        // MSTEST0015 fires even when [Ignore] has a justification message.
+        // The presence of a message satisfies MSTEST0066 (IgnoreShouldHaveJustification),
+        // but the method is still ignored and MSTEST0015 still applies.
+        string code = """
+            using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+            [TestClass]
+            public class MyTestClass
+            {
+                [Ignore("Tracked by #12345")]
+                [TestMethod]
+                public void {|#0:MyTestMethod|}()
+                {
+                }
+            }
+            """;
+
+        await VerifyCS.VerifyAnalyzerAsync(
+            code,
+            VerifyCS.Diagnostic(TestMethodShouldNotBeIgnoredAnalyzer.TestMethodShouldNotBeIgnoredRule)
+                .WithLocation(0)
+                .WithArguments("MyTestMethod"));
+    }
 }