[test-improver] test: add edge case tests for DoNotUseSystemDescriptionAttributeAnalyzer (MSTEST0031)

[Evangelink]

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Goal and Rationale

DoNotUseSystemDescriptionAttributeAnalyzer (MSTEST0031) had 5 tests covering the main diagnostic and code-fix paths, but two real-world behaviors were undocumented:

1. [DataTestMethod] + [System.ComponentModel.Description] → diagnostic — DataTestMethodAttribute inherits from TestMethodAttribute. The analyzer detects test methods via attribute.AttributeClass.Inherits(testMethodAttributeSymbol), so [DataTestMethod] should trigger the same diagnostic as [TestMethod]. No test confirmed this inheritance path.

2. [TestMethod] + MSTest's [Description] → no diagnostic — When using Microsoft.VisualStudio.TestTools.UnitTesting is in scope (without using System.ComponentModel), the short-form [Description] resolves to Microsoft.VisualStudio.TestTools.UnitTesting.DescriptionAttribute — the correct attribute. The analyzer checks via SymbolEqualityComparer.Default.Equals(attribute.AttributeClass, systemDescriptionAttributeSymbol) (not Inherits()), so it must not fire here. This test guards against a future regression that might accidentally flag the correct usage.

Approach

Added 2 new [TestMethod] test cases to DoNotUseSystemDescriptionAttributeAnalyzerTests. No production code changes.

Test Status

Test run summary: Passed!
  total: 7
  failed: 0
  succeeded: 7
  skipped: 0
  duration: 8s 605ms

✅ All 7 tests pass (MSTest.Analyzers.UnitTests, net8.0, Debug — 5 original + 2 new).

Reproducibility

./build.sh --restore   # first run only
.dotnet/dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj \
  -f net8.0 --no-build -c Debug \
  --filter "ClassName=MSTest.Analyzers.Test.DoNotUseSystemDescriptionAttributeAnalyzerTests"

Trade-offs

• Tests exercise existing code paths only — no production changes, no maintenance burden beyond the tests.
• The [DataTestMethod] test pins the Inherits() check behavior for derived test-method attributes.
• The MSTest [Description] test guards against accidentally flagging the correct usage.

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Pull request overview

This PR expands unit test coverage for the DoNotUseSystemDescriptionAttributeAnalyzer (MSTEST0031) in MSTest.Analyzers.UnitTests by adding two edge-case tests that document and lock in real-world attribute resolution/inheritance behavior.

Changes:

• Add a new diagnostic + code-fix test ensuring [DataTestMethod] (derived from TestMethodAttribute) is treated as a test method and still triggers MSTEST0031 when using System.ComponentModel.DescriptionAttribute.
• Add a new “no diagnostic” test ensuring short-form [Description] resolves to MSTest’s Microsoft.VisualStudio.TestTools.UnitTesting.DescriptionAttribute when only the MSTest namespace is imported, and is not incorrectly flagged.

Show a summary per file

File	Description
test/UnitTests/MSTest.Analyzers.UnitTests/DoNotUseSystemDescriptionAttributeAnalyzerTests.cs	Adds two edge-case unit tests covering DataTestMethod inheritance detection and MSTest [Description] short-name resolution without triggering the analyzer.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0

[Evangelink]

🧪 Test quality grade — PR #9020

Δ	Test	Grade	Band	Notes
new	DoNotUseSystemDescriptionAttributeAnalyzerTests. WhenDataTestMethodHasSystemDescriptionAttribute_ Diagnostic	A	90–100	VerifyCodeFixAsync asserts diagnostic location and fix output; comment explains DataTestMethod inheritance rationale.
new	DoNotUseSystemDescriptionAttributeAnalyzerTests. WhenTestMethodHasMSTestDescriptionAttribute_ NoDiagnostic	A	90–100	No-diagnostic test; VerifyAnalyzerAsync asserts analyzer is silent for MSTest-namespaced Description attribute.

_{This advisory comment was generated automatically. Grades are heuristic
and informational — they do not block merging. Re-run with
/grade-tests.}

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[Evangelink]

Note

🤖 Automated review by GitHub Copilot. Posted via a maintainer's GitHub token, so it appears under their account — the account owner did not write or approve this content personally. Generated by the Expert Code Review workflow. To request a follow-up action, reply by tagging @copilot directly.

✅ 22/22 dimensions clean — no findings.

Dimension coverage notes (test-only PR)

#	Dimension	Status
1	Algorithmic Correctness	✅ Clean
2	Threading & Concurrency	— N/A
3	Security & IPC Contract Safety	— N/A
4	Public API & Binary Compatibility	— N/A
5	Performance & Allocations	— N/A
6	Cross-TFM Compatibility	— N/A
7	Resource & IDisposable Management	— N/A
8	Defensive Coding at Boundaries	— N/A
9	Localization & Resources	— N/A
10	Test Isolation	✅ Clean
11	Assertion Quality	✅ Clean
12	Flakiness Patterns	✅ Clean
13	Test Completeness & Coverage	✅ Clean
14	Data-Driven Test Coverage	✅ Clean
15	Code Structure & Simplification	✅ Clean
16	Naming & Conventions	✅ Clean
17	Documentation Accuracy	✅ Clean
18	Analyzer & Code Fix Quality	— N/A (no src/Analyzers change)
19	IPC Wire Compatibility	— N/A
20	Build Infrastructure & Dependencies	— N/A
21	Scope & PR Discipline	✅ Clean
22	PowerShell Scripting Hygiene	— N/A

Notable verifications:

• WhenDataTestMethodHasSystemDescriptionAttribute_Diagnostic: The [|MyTestMethod|] diagnostic marker correctly targets the method name, matching methodSymbol.CreateDiagnostic(..., methodSymbol.Name) in the analyzer. The code fix correctly preserves [DataRow(1)] and replaces [System.ComponentModel.Description(...)] with the short-form [Description(...)] (which resolves to Microsoft.VisualStudio.TestTools.UnitTesting.DescriptionAttribute because using Microsoft.VisualStudio.TestTools.UnitTesting; is in scope — as confirmed by the companion WhenTestMethodHasMSTestDescriptionAttribute_NoDiagnostic test).
• WhenTestMethodHasMSTestDescriptionAttribute_NoDiagnostic: Accurately guards against a regression where SymbolEqualityComparer.Default.Equals(attribute.AttributeClass, systemDescriptionAttributeSymbol) might be broadened to Inherits(). The absence of using System.ComponentModel; ensures [Description] resolves to the MSTest attribute, which is a different symbol from System.ComponentModel.DescriptionAttribute, so the analyzer correctly stays silent.
• Comments in both tests accurately describe the Inherits() vs. SymbolEqualityComparer.Default.Equals() distinction, providing valuable context for future contributors.

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