Add acceptance tests for duplicate TestMethod and TestClass attributes by Copilot · Pull Request #7224 · microsoft/testfx

Copilot · 2026-01-14T11:41:15Z

Adds MSTest acceptance tests validating that duplicate attributes derived from TestMethodAttribute and TestClassAttribute are properly detected and reported as failures.

Test Coverage

The tests validate two distinct failure scenarios:

Duplicate TestMethod attributes: Test class with both [TestMethod] and custom [MyTestMethod] attributes on the same method, which causes one test to fail while other tests in the class pass
Duplicate TestClass attributes: Test class with both [TestClass] and custom [MyTestClass] attributes that should fail with proper error message

Test Structure

Two separate test methods with dedicated test assets provide focused validation:

DuplicateTestMethodAttribute_ShouldFail: Uses the DuplicateTestMethodAttribute test asset and validates that the exit code is AtLeastOneTestFailed with 1 test passing and 1 test failing
DuplicateTestClassAttribute_ShouldFail: Uses the DuplicateTestClassAttribute test asset and validates that duplicate TestClass attributes cause a failure with the expected error message "Multiple attributes of type 'Microsoft.VisualStudio.TestTools.UnitTesting.TestClassAttribute' found."

DuplicateTestMethodAttribute Test Asset

[TestClass]
public class TestClass1
{
    [TestMethod]
    [MyTestMethod]  // Duplicate TestMethod attribute - causes this test to fail
    public void Test1() { }

    [TestMethod]
    public void Test2() { }  // This test passes
}

public class MyTestMethodAttribute : TestMethodAttribute
{
    public MyTestMethodAttribute([CallerFilePath] string callerFilePath = "", [CallerLineNumber] int callerLineNumber = -1)
        : base(callerFilePath, callerLineNumber) { }
}

DuplicateTestClassAttribute Test Asset

[TestClass]
[MyTestClass]  // Duplicate TestClass attribute - causes discovery failure
public class TestClass2
{
    [TestMethod]
    public void Test1() { }
}

public class MyTestClassAttribute : TestClassAttribute { }

The tests validate that duplicate attributes are properly detected and reported, ensuring appropriate error handling for both duplicate TestMethod and TestClass attribute scenarios.

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- Created CustomAttributesTests.cs in MSTest.Acceptance.IntegrationTests - Test verifies that custom attributes derived from TestMethodAttribute and TestClassAttribute work correctly - Covers scenario with CallerFilePath and CallerLineNumber parameters - Tests both custom TestMethod attribute on test methods and custom TestClass attribute on test classes Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>

Copilot · 2026-01-14T11:45:56Z

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

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test/IntegrationTests/MSTest.Acceptance.IntegrationTests/CustomAttributesTests.cs

The TestContext property is automatically set by MSTest framework and is used to access the cancellation token in the test method. Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>

test/IntegrationTests/MSTest.Acceptance.IntegrationTests/CustomAttributesTests.cs

- CustomTestMethodAttribute_ShouldDiscoverAndRun: filters for TestClass1 (2 tests) - CustomTestClassAttribute_ShouldDiscoverAndRun: filters for TestClass2 (1 test) This provides better test isolation and clearer validation of each scenario. Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>

Youssef1313 · 2026-01-14T12:58:27Z

test/IntegrationTests/MSTest.Acceptance.IntegrationTests/CustomAttributesTests.cs

+
+    [TestMethod]
+    [DynamicData(nameof(TargetFrameworks.AllForDynamicData), typeof(TargetFrameworks))]
+    public async Task CustomTestClassAttribute_ShouldDiscoverAndRun(string tfm)


@copilot

Rename this test to DuplicateTestClassAttribute_ShouldFail

Assert exit code is not success.

Assert output contains "Multiple attributes of type 'Microsoft.VisualStudio.TestTools.UnitTesting.TestClassAttribute' found."

Updated in commit 8f4cfd8:

Renamed test to DuplicateTestClassAttribute_ShouldFail

Changed assertion to AssertExitCodeIsNot(ExitCodes.Success)

Added assertion for error message: "Multiple attributes of type 'Microsoft.VisualStudio.TestTools.UnitTesting.TestClassAttribute' found."

- Renamed CustomTestClassAttribute_ShouldDiscoverAndRun to DuplicateTestClassAttribute_ShouldFail - Changed assertion to expect non-success exit code - Added assertion to verify error message about duplicate TestClassAttribute Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>

Youssef1313 · 2026-01-14T13:00:13Z

test/IntegrationTests/MSTest.Acceptance.IntegrationTests/CustomAttributesTests.cs

+
+    [TestMethod]
+    [DynamicData(nameof(TargetFrameworks.AllForDynamicData), typeof(TargetFrameworks))]
+    public async Task CustomTestMethodAttribute_ShouldDiscoverAndRun(string tfm)


@copilot

Rename this test to DuplicateTestMethodAttribute_ShouldFail

Assert exit code is AtLeastOneTestFailed, and assert that one test passes and one failed.

In addition, use two different test assets for the two tests.

Updated in commit 0a42af8:

Renamed first test to DuplicateTestMethodAttribute_ShouldFail

Changed assertion to AssertExitCodeIs(ExitCodes.AtLeastOneTestFailed)

Added assertion for summary: 1 passed, 1 failed

Created two separate test assets:

DuplicateTestMethodAttribute for testing duplicate TestMethod attributes

DuplicateTestClassAttribute for testing duplicate TestClass attributes

- Renamed first test to DuplicateTestMethodAttribute_ShouldFail - Changed assertion to AssertExitCodeIs(ExitCodes.AtLeastOneTestFailed) - Added assertion for 1 passed, 1 failed test summary - Split test assets into two separate projects: - DuplicateTestMethodAttribute: Tests duplicate TestMethod attributes - DuplicateTestClassAttribute: Tests duplicate TestClass attributes - Removed filters as each test now has its own dedicated test asset Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>

Initial plan

a1854cc

Copilot AI assigned Copilot and Youssef1313 Jan 14, 2026

Copilot AI mentioned this pull request Jan 14, 2026

Fix TypeCache to throw on duplicate attributes when necessary #7223

Merged

Copilot started work on behalf of Youssef1313 January 14, 2026 11:41 View session

Copilot AI changed the title ~~[WIP] Fix TypeCache to throw on duplicate attributes when necessary~~ Add acceptance test for custom TestMethod and TestClass attributes Jan 14, 2026

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Copilot started work on behalf of Youssef1313 January 14, 2026 11:54 View session

Add TestContext property to CustomAttributesTests

7a5efa1

The TestContext property is automatically set by MSTest framework and is used to access the cancellation token in the test method. Co-authored-by: Youssef1313 <31348972+Youssef1313@users.noreply.github.com>

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Copilot AI changed the title ~~Add acceptance test for custom TestMethod and TestClass attributes~~ Add acceptance tests for duplicate TestMethod and TestClass attributes Jan 14, 2026

Copilot finished work on behalf of Youssef1313 January 14, 2026 13:05

Youssef1313 added 2 commits January 14, 2026 14:55

Fix formatting

e7bba11

stderr

1c22672

Youssef1313 marked this pull request as ready for review January 14, 2026 14:15

Youssef1313 merged commit e9a3c71 into dev/ygerges/single-attribute Jan 14, 2026
2 of 7 checks passed

Youssef1313 deleted the copilot/sub-pr-7223 branch January 14, 2026 14:15

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Add acceptance tests for duplicate TestMethod and TestClass attributes#7224

Add acceptance tests for duplicate TestMethod and TestClass attributes#7224
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Copilot AI commented Jan 14, 2026 •

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Test Coverage

Test Structure

DuplicateTestMethodAttribute Test Asset

DuplicateTestClassAttribute Test Asset

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Copilot AI commented Jan 14, 2026 •

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