[test-improver] test: add edge case tests for UseAttributeOnTestMethodAnalyzer (MSTEST0007)

[Amaury Levé (Evangelink)]

Goal and Rationale

UseAttributeOnTestMethodAnalyzer (MSTEST0007) had 37 test cases via 11 test methods (several using DynamicData), but two distinct code paths in the analyzer's logic were not covered:

Untested path	Guard
Standard [DataTestMethod] causes early-return (no diagnostic)	methodAttribute.AttributeClass.Inherits(testMethodAttributeSymbol) early-return — previously only tested with a custom MyCustomTestMethodAttribute
Non-[Ignore] ConditionBase subclass fires ConditionBaseRule with the concrete class name	ReferenceEquals(attribute.Rule, ConditionBaseRule) → attribute.AttributeData.AttributeClass.Name — previously only [Ignore] was tested

Approach

Added two [TestMethod] entries to UseAttributeOnTestMethodAnalyzerTests.cs:

Test	What it covers
WhenMethodIsMarkedWithDataTestMethodAndTestAttribute_NoDiagnosticAsync	[DataTestMethod] + [Owner("owner")] → no diagnostic. Validates that the standard DataTestMethodAttribute (which inherits TestMethodAttribute) also causes early-return in the analyzer, not just user-defined subclasses.
WhenMethodIsMarkedWithOSConditionAttributeButNotWithTestMethod_DiagnosticAsync	[OSCondition(OperatingSystems.Windows)] on a method with no [TestMethod] → ConditionBaseRule with argument "OSConditionAttribute". Validates the ConditionBaseRule branch for a non-[Ignore] subclass of ConditionBaseAttribute.

Coverage Impact

	Before	After
Tests in UseAttributeOnTestMethodAnalyzerTests	37	39

Trade-offs

Purely additive — no production code changes, no new dependencies.

Test Status

All 39/39 tests pass (net8.0, Debug):

Test run summary: Passed!
  total: 39
  failed: 0
  succeeded: 39
  duration: 7s 251ms

Reproducibility

.dotnet/dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj \
  -f net8.0 --no-build -c Debug \
  --filter "FullyQualifiedName~UseAttributeOnTestMethodAnalyzerTests"

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Pull request overview

Adds targeted unit tests to improve coverage for UseAttributeOnTestMethodAnalyzer (MSTEST0007) in the MSTest analyzers test suite, specifically exercising previously untested branches around DataTestMethod inheritance and ConditionBaseAttribute-derived conditions.

Changes:

• Add a no-diagnostic test validating the analyzer’s early-return behavior when [DataTestMethod] is present (as a TestMethodAttribute subclass).
• Add a diagnostic + code-fix test validating the ConditionBaseRule path for [OSCondition(...)] when [TestMethod] is missing.

Show a summary per file

File	Description
test/UnitTests/MSTest.Analyzers.UnitTests/UseAttributeOnTestMethodAnalyzerTests.cs	Adds two new test methods to cover DataTestMethodAttribute early-return and non-Ignore ConditionBaseAttribute diagnostic behavior.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 1
• Review effort level: Low

[Copilot]

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0 new
• Review effort level: Low

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9516

Δ	Test	Grade	Band	Notes
new	UseAttributeOnTestMethodAnalyzerTests. WhenMethodIsMarkedWithOSConditionAttributeButNotWithTestMethod_ DiagnosticAsync	B	80–89	Body is slightly over ~30 lines (~36) due to the code-fix pattern needing both input and expected-output snippets; assertions thoroughly verify the diagnostic rule, location, arguments, and fix output.
new	UseAttributeOnTestMethodAnalyzerTests. WhenMethodIsMarkedWithDataTestMethodAndOwnerAttribute_ NoDiagnosticAsync	A	90–100	No issues found.

_{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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[Amaury Levé (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

#	Dimension	Verdict
1	Algorithmic Correctness	✅ LGTM
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	✅ LGTM
11	Assertion Quality	✅ LGTM
12	Flakiness Patterns	✅ LGTM
13	Test Completeness & Coverage	✅ LGTM
14	Data-Driven Test Coverage	✅ LGTM
15	Code Structure & Simplification	✅ LGTM
16	Naming & Conventions	✅ LGTM
17	Documentation Accuracy	✅ LGTM
18	Analyzer & Code Fix Quality	✅ LGTM
19	IPC Wire Compatibility	N/A
20	Build Infrastructure & Dependencies	N/A
21	Scope & PR Discipline	✅ LGTM
22	PowerShell Scripting Hygiene	N/A

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Notes

Test 1 (WhenMethodIsMarkedWithDataTestMethodAndOwnerAttribute_NoDiagnosticAsync) — Correctly validates the early-return path in AnalyzeSymbol. DataTestMethodAttribute inherits TestMethodAttribute, so methodAttribute.AttributeClass.Inherits(testMethodAttributeSymbol) returns true and the method exits before collecting any diagnostics — regardless of attribute ordering in GetAttributes(). The [Owner("owner")] companion attribute is a suitable witness that a diagnostic would have been emitted had the early-return not triggered. Clean.

Test 2 (WhenMethodIsMarkedWithOSConditionAttributeButNotWithTestMethod_DiagnosticAsync) — Correctly exercises the ReferenceEquals(attribute.Rule, ConditionBaseRule) branch for a non-[Ignore] subclass. OSConditionAttribute : ConditionBaseAttribute is confirmed in source; OperatingSystems.Windows is a valid enum value in Microsoft.VisualStudio.TestTools.UnitTesting; attribute.AttributeData.AttributeClass.Name yields "OSConditionAttribute", matching .WithArguments("OSConditionAttribute"). The code fix expectation (inserting [TestMethod] below the condition attribute) is consistent with the fixer's existing behaviour verified by the [Ignore] analogue. Clean.

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Pre-existing observation (not introduced by this PR)

ConditionBaseRule is absent from SupportedDiagnostics (line 119–125 of UseAttributeOnTestMethodAnalyzer.cs), while it is present in RuleTuples. This does not cause a runtime failure because all six rule descriptors share the same DiagnosticIds.UseAttributeOnTestMethodRuleId ID, and Roslyn filters by ID when deciding whether a reported diagnostic is supported. However, the missing entry means IDE tooling cannot surface ConditionBaseRule's distinct title/message-format in the analyzer catalog. The existing [Ignore] test — and now the new OSCondition test — both exercise this descriptor without issue, confirming the gap is benign in practice. Worth tracking separately if full descriptor fidelity in the manifest matters.