test: MSTEST0029 — add edge case tests for virtual/override and make-private fixer

[Evangelink]

Fixes #9758.

Improves test coverage for PublicMethodShouldBeTestMethodAnalyzer (MSTEST0029) by closing gaps in the existing test suite.

Changes

test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs

• Add WhenPublicVirtualMethodInTestClass_NoDiagnostic — exercises the IsVirtual early-return path: a public virtual method in a [TestClass] that does not implement any interface should produce no diagnostic.
• Add WhenPublicOverrideMethodInTestClass_NoDiagnostic — exercises the IsOverride early-return path: a public override of a non-interface base-class method in a [TestClass] should produce no diagnostic.
• Add WhenMethodIsPublicAndNotMarkedAsTestMethod_ChangeToPrivateFix — exercises CodeActionIndex = 1, the "Change accessibility to private" code fix offered by PublicMethodShouldBeTestMethodFixer, which was previously untested.
• Fix WhenMethodIsPublicAndMarkedAsTestCleanup_NoDiagnostic — the test body used [TestInitialize] instead of [TestCleanup], making it a duplicate of the TestInitialize test and leaving the [TestCleanup] suppression path untested.

Test status

Pure test additions — no production code changed. All 19 PublicMethodShouldBeTestMethodAnalyzerTests pass:

Test run summary: Passed!
  total: 19, failed: 0, succeeded: 19, skipped: 0

[Copilot]

Pull request overview

This PR improves unit-test coverage for PublicMethodShouldBeTestMethodAnalyzer (MSTEST0029) by closing three gaps in PublicMethodShouldBeTestMethodAnalyzerTests.cs and correcting one misleading existing test. It is a test-only change with no production code touched. The additions correctly target the analyzer's IsVirtual/IsOverride early-return branches and the fixer's previously-untested "change accessibility to private" code action.

Changes:

• Adds WhenPublicVirtualMethodInTestClass_NoDiagnostic and WhenPublicOverrideMethodInTestClass_NoDiagnostic to cover the analyzer's virtual/override suppression paths.
• Adds WhenMethodIsPublicAndNotMarkedAsTestMethod_ChangeToPrivateFix to cover the fixer's second code action (CodeActionIndex = 1).
• Fixes WhenMethodIsPublicAndMarkedAsTestCleanup_NoDiagnostic to actually use [TestCleanup] instead of [TestInitialize], so the cleanup suppression path is genuinely exercised.

Show a summary per file

File	Description
test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs	Adds three new tests (virtual, override, change-to-private fixer) and corrects the [TestCleanup] test body; all consistent with existing verifier patterns and diagnostic-location conventions.

Review details

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

[github-actions]

🔍 Build Failure Analysis

Summary — The build fails because two new protected static methods in BaseSerializer.cs (ReadFields and WriteListPayload<T>) are not declared in the internal API tracking file. This is a pre-existing issue on main — it is unrelated to the test-only changes in this PR.

Root cause: Undeclared internal API members (RS0051)

The Microsoft.Testing.Platform project tracks its internal API surface via InternalAPI/InternalAPI.Shipped.txt and InternalAPI/InternalAPI.Unshipped.txt files. Two recently-added methods in BaseSerializer.cs were not registered in InternalAPI.Unshipped.txt, causing the Roslyn public API analyzer (RS0051) to fire on all three target frameworks (net8.0, net9.0, netstandard2.0).

The failure in Microsoft.Testing.Platform.csproj cascades to all downstream projects (Microsoft.Testing.Extensions.AzureDevOpsReport, Microsoft.Testing.Extensions.CrashDump, etc.) since they depend on it.

Affected symbols

Method	File	Line
BaseSerializer.ReadFields(Stream, Func<ushort, int, bool>)	BaseSerializer.cs:359	359
BaseSerializer.WriteListPayload<T>(Stream, ushort, T[]?, Action<Stream, T>)	BaseSerializer.cs:380	380

Proposed fix

Add the following two lines to src/Platform/Microsoft.Testing.Platform/InternalAPI/InternalAPI.Unshipped.txt:

 #nullable enable
+static Microsoft.Testing.Platform.IPC.Serializers.BaseSerializer.ReadFields(System.IO.Stream! stream, System.Func<ushort, int, bool>! tryReadField) -> void
+static Microsoft.Testing.Platform.IPC.Serializers.BaseSerializer.WriteListPayload<T>(System.IO.Stream! stream, ushort fieldId, T[]? list, System.Action<System.IO.Stream!, T>! writeItem) -> void

Note: Since BaseSerializer is an internal abstract class and its other members are already tracked in the common InternalAPI/InternalAPI.Shipped.txt file (not the net/-specific one), the fix belongs in the common InternalAPI/InternalAPI.Unshipped.txt.

Impact on this PR: This PR only adds test cases to PublicMethodShouldBeTestMethodAnalyzerTests.cs — no production code was changed. The build failure is inherited from main and should be fixed there (or in this branch as a drive-by fix to unblock CI).

---

Build overview

Property	Value
Status	FAILED
Duration	154.3 s
MSBuild	18.8.0-preview-26302-115+f7b4c5716
Projects	49
Errors	7 (6 × RS0051 + 1 "Build failed")
Failed project	Microsoft.Testing.Platform.csproj (net8.0, net9.0, netstandard2.0)
Cascading failures	NonWindowsTests.slnf, AzureDevOpsReport.csproj, CrashDump.csproj

All MSBuild errors (7)

Code	TFM	File:Line	Message
RS0051	net8.0	BaseSerializer.cs:359	ReadFields(...) is not part of the declared API
RS0051	net9.0	BaseSerializer.cs:359	ReadFields(...) is not part of the declared API
RS0051	netstandard2.0	BaseSerializer.cs:359	ReadFields(...) is not part of the declared API
RS0051	net8.0	BaseSerializer.cs:380	WriteListPayload<T>(...) is not part of the declared API
RS0051	net9.0	BaseSerializer.cs:380	WriteListPayload<T>(...) is not part of the declared API
RS0051	netstandard2.0	BaseSerializer.cs:380	WriteListPayload<T>(...) is not part of the declared API
—	—	—	Build failed.

---

_{🤖 Generated by the Build Failure Analysis workflow using (a href="(dev.azure.com/redacted) · commit 2839244}

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[github-actions]

Note

🤖 Automated review by GitHub Copilot. Generated by the Expert Code Review workflow. To request a follow-up action, reply by tagging @copilot directly.

✅ 22/22 dimensions clean — no findings.

Applicable dimensions verified (all clean): Algorithmic Correctness, Test Isolation, Assertion Quality, Test Completeness, Code Structure, Naming & Conventions, Analyzer & Code Fix Quality, Scope & PR Discipline.

N/A dimensions (test-only PR, no production code): Threading, Security, Public API, Performance, Cross-TFM, Resource Management, Defensive Coding, Localization, Flakiness, Data-Driven, Documentation, IPC Wire, Build Infrastructure, PowerShell.

Notes:

• The [TestInitialize] → [TestCleanup] fix correctly eliminates a duplicate of the TestInitialize test and restores coverage of the testCleanupAttributeSymbol suppression path.
• The new virtual/override tests appropriately use VerifyCS.VerifyAnalyzerAsync (analyzer-only verification) since these paths produce no diagnostic and no code-fix action is relevant.
• The CodeActionIndex = 1 test correctly exercises the second registered code action (ChangeMethodAccessibilityToPrivateFix) from the fixer.

[Copilot]

Review details

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

[github-actions]

🧪 Test quality grade — PR #9785

Grade	Test	Notes
A (90–100)	mod PublicMethodShouldBeTestMethodAnalyzerTests. WhenMethodIsPublicAndMarkedAsTestCleanup_ NoDiagnostic	No issues found.
A (90–100)	new PublicMethodShouldBeTestMethodAnalyzerTests. WhenMethodIsPublicAndNotMarkedAsTestMethod_ ChangeToPrivateFix	Verifies both diagnostic detection and the "make private" code fix; CodeActionIndex = 1 is clear from the method name and fixedCode, though a brief inline comment (e.g. // change-to-private fix) would help future readers.
A (90–100)	new PublicMethodShouldBeTestMethodAnalyzerTests. WhenPublicOverrideMethodInTestClass_ NoDiagnostic	No issues found.
A (90–100)	new PublicMethodShouldBeTestMethodAnalyzerTests. WhenPublicVirtualMethodInTestClass_ NoDiagnostic	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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