[test-improver] test: add edge case tests for RemoveClassCleanupBehaviorArgumentFixer

[Amaury Levé (Evangelink)]

Goal and Rationale

RemoveClassCleanupBehaviorArgumentFixer had only 2 tests covering the "happy path" (sole argument removed, second of two arguments removed). Two code paths inside the fixer were completely untested:

1. ClassCleanupBehavior as the first of two arguments — the fixer removes the first argument and preserves the remaining InheritanceBehavior argument. This is the mirror of the existing test where ClassCleanupBehavior is second.
2. attributeArgument is null guard — when a CS0103 diagnostic for ClassCleanupBehavior fires outside an attribute argument (e.g. in a method body), the fixer explicitly skips registration. This path was never exercised by a test.

Approach

Added two new [TestMethod] entries to RemoveClassCleanupBehaviorArgumentFixerTests.cs:

Test	What it covers
WhenClassCleanupBehaviorIsFirstArgument_RemovesBehaviorKeepsInheritance	[ClassCleanup(ClassCleanupBehavior.EndOfClass, InheritanceBehavior.None)] → [ClassCleanup(InheritanceBehavior.None)]
WhenClassCleanupBehaviorReferencedOutsideAttribute_NoFix	_ = ClassCleanupBehavior.EndOfClass; in a method body — no fix registered, code unchanged

Trade-offs

Both tests are simple and low-maintenance. The "no fix" test uses VerifyCodeFixAsync(code, code), the same pattern used elsewhere in the codebase for cases where a diagnostic fires but no fix is appropriate.

Test Status

All 4 tests pass (2 pre-existing + 2 new):

passed WhenClassCleanupBehaviorArgument_Simple
passed WhenClassCleanupBehaviorWithMultiLineBody_PreservesIndentation
passed WhenClassCleanupBehaviorIsFirstArgument_RemovesBehaviorKeepsInheritance  ← new
passed WhenClassCleanupBehaviorReferencedOutsideAttribute_NoFix                 ← new

Command:

.dotnet/dotnet run --project test/UnitTests/MSTest.Analyzers.UnitTests/ -f net8.0 --no-build -c Debug -- --filter "FullyQualifiedName~RemoveClassCleanupBehaviorArgumentFixerTests"

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[Copilot]

Pull request overview

Adds missing unit-test coverage for RemoveClassCleanupBehaviorArgumentFixer (MSTest analyzers) by exercising two previously untested branches: removing ClassCleanupBehavior when it is the first of two arguments, and ensuring no fix is offered when ClassCleanupBehavior appears outside an attribute argument.

Changes:

• Add a test where ClassCleanupBehavior is the first argument and verify the fixer preserves the remaining InheritanceBehavior argument.
• Add a test ensuring no fix is registered when the ClassCleanupBehavior compiler diagnostic occurs in a method body (non-attribute context).

Show a summary per file

File	Description
test/UnitTests/MSTest.Analyzers.UnitTests/RemoveClassCleanupBehaviorArgumentFixerTests.cs	Adds two new test methods covering the fixer’s “first argument” removal path and its “not inside attribute argument” no-op guard.

Copilot's findings

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

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9410

Δ	Test	Grade	Band	Notes
new	RemoveClassCleanupBehaviorArgumentFixerTests. WhenClassCleanupBehaviorIsFirstArgument_ RemovesBehaviorKeepsInheritance	B	80–89	Correct assertion; body runs ~46 lines (inflated by required Roslyn code snippets) — mild length concern.
new	RemoveClassCleanupBehaviorArgumentFixerTests. WhenClassCleanupBehaviorReferencedOutsideAttribute_ NoFix	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.}

🤖 Automated content 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 Grade Tests on PR (on open / sync) workflow. · 226.3 AIC · ⌖ 13.7 AIC · ⊞ 43.7K · [◷]( · ◷)

[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.

✅ 10/10 applied dimensions clean — no findings.

Skipped (not applicable to a test-only diff): Threading & Concurrency, Security & IPC Contract Safety, Public API & Binary Compatibility, Performance & Allocations, Cross-TFM Compatibility, Resource & IDisposable Management, Defensive Coding at Boundaries, Localization & Resources, Analyzer & Code Fix Quality (src), IPC Wire Compatibility, Build Infrastructure & Dependencies, PowerShell Scripting Hygiene.

Applied dimensions:

#	Dimension	Verdict
1	Algorithmic Correctness	✅ LGTM
2	Test Isolation	✅ LGTM
3	Assertion Quality	✅ LGTM
4	Flakiness Patterns	✅ LGTM
5	Test Completeness & Coverage	✅ LGTM
6	Data-Driven Test Coverage	✅ LGTM
7	Code Structure & Simplification	✅ LGTM
8	Naming & Conventions	✅ LGTM
9	Documentation Accuracy	✅ LGTM
10	Scope & PR Discipline	✅ LGTM

Notes:

• Algorithmic Correctness: Both diagnostic markers are correct. {|CS0103:ClassCleanupBehavior|} fires because the type is gone; {|CS1729:ClassCleanup(...)|} fires because no overload matches the erroneous first argument — exactly mirroring the second-argument pattern already exercised in WhenClassCleanupBehaviorArgument_Simple. The fixer's RemoveNode(attributeArgument, SyntaxRemoveOptions.KeepNoTrivia) on a SeparatedSyntaxList removes the first element and its following separator, producing (InheritanceBehavior.None) with no stray space — consistent with the expected fixedCode.

• No-fix guard path: VerifyCodeFixAsync(code, code) is the correct idiom for asserting that no fix is registered. The guard in the fixer (attributeArgument is null → skip registration) is cleanly exercised by placing the CS0103 reference inside a method body statement, not inside any AttributeArgumentSyntax ancestor.

• Inline comments: The // Exercises the branch... comments in the new test bodies are the only body-level comments in the file. They fall within the project's "comment what needs clarification" guideline and genuinely help readers understand which fixer branch is being targeted without requiring them to trace into the fixer implementation.