[Diagnostic] Strengthen #52029 repro and unskip IncludeTestAssembly=true cases

[Evangelink]

Follow-up to #54514 / #52029 — diagnostic to prove-or-disprove the bug.

Why

Reviewer @Youssef1313 pointed out on #54514 (comment) that it's unclear whether issue #52029 (BadImageFormatException: Index not found on Linux/macOS when IncludeTestAssembly=true) actually still reproduces. PR #54514 just parameterized the existing test on IncludeTestAssembly and skipped the =true cases with a link to the issue, but the original test asset is so minimal that the bug would never trigger anyway — so a green CI on those skips would have proved nothing.

Concretely, StaticManagedInstrumenter.InstrumentAsync short-circuits when both <IncludeDirectories> and <AdditionalFiles> are empty in the coverage config. The merged coverage.config only sets <IncludeTestAssembly>, so the instrumenter never actually rewrote any IL and the historical crash path was never exercised.

What this PR does (diagnostic)

1. Adds a Lib class library with async methods (Task.Yield/Task.Delay loops, IAsyncEnumerable) so there are real async state machines for the static instrumenter to rewrite.
2. Adds async test methods that exercise Lib so the test assembly itself has async patterns (matching the original crash stack which was during async cleanup).
3. Writes a richer coverage.config that explicitly enables static managed instrumentation and populates <ModulePaths><IncludeDirectories> pointing at the test project bin folder, defeating the early-return.
4. Unskips both IncludeTestAssembly=true cases.
5. Updates the test summary assertion to reflect the new total (6 tests / 5 passed / 1 failed).

What to do with the CI results

• If CI fails on Linux/macOS with the historic BadImageFormatException / exit code 134 → bug is confirmed. I'll re-skip the =true rows but with the stronger repro committed, so the skip is actually meaningful and a future fix can be validated against this test.
• If CI is green across the board → bug really doesn't reproduce anymore, the unskip stands, and I'll mark this PR Ready and we can close Skipped test: Microsoft.DotNet.Cli.Test.Tests.GivenDotnetTestBuildsAndRunsTestsWithArtifacts.RunTestProjectWithCodeCoverage_ShouldReturnExitCodeGenericFailure #52029 for good.

Marking as Draft until CI tells us which branch we're on.

cc @Youssef1313 @Evangelink

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Evangelink]

CI results: the bug does NOT reproduce even with the strengthened repro

I dug into the macOS x64 + Windows x64 Helix runs of build 1448073. The previously-skipped includeTestAssembly: True cases now run, and they pass everywhere:

Windows x64 (Helix job 4f509454-26b8-4242-bd01-92f88ab91d77, 449/449 work items passed) — dotnet.Tests.dll.20 shows:

Passed ...RunTestProjectWithCodeCoverage_ShouldReturnExitCodeAtLeastOneTestFailed(configuration: "Release", includeTestAssembly: False) [12 s]
Passed ...RunTestProjectWithCodeCoverage_ShouldReturnExitCodeAtLeastOneTestFailed(configuration: "Debug",   includeTestAssembly: False) [6 s]
Passed ...RunTestProjectWithCodeCoverage_ShouldReturnExitCodeAtLeastOneTestFailed(configuration: "Release", includeTestAssembly: True)  [6 s]
Passed ...RunTestProjectWithCodeCoverage_ShouldReturnExitCodeAtLeastOneTestFailed(configuration: "Debug",   includeTestAssembly: True)  [6 s]

macOS x64 (Helix job 50bb077d-212b-4c49-8440-8761c2d7918e, our partition dotnet.Tests.dll.20 passed in 6m 2s) — same 4 outcomes, all Passed. No BadImageFormatException, no crash, no exit 134; the inner dotnet test exits with 2 (TestingPlatform "tests failed") as expected.

What the inner test produced (snippet from includeTestAssembly: True on macOS x64):

failed TestMethod2 (18ms)
  Assertion failed. Expected values to be equal.
  expected: 1
  actual:   2
  Assert.AreEqual(1, 2)
    at TestProject.Test1.TestMethod2()
Exit code: 2

The strengthened test asset (Lib with AsyncCalculator — Task.Yield/Task.Delay loops + IAsyncEnumerable) and the coverage.config explicitly enabling EnableStaticManagedInstrumentation + recursive ModulePaths/IncludeDirectories pointing at the test output did not trigger #52029. Static instrumentation runs cleanly against the test assembly + Lib.dll.

About the other red checks (all unrelated)

• Linux x64 build: MSB3894/MSB3026 "process cannot access file" on Microsoft.DotNet.GenAPI.Tool resource DLLs during parallel publish — classic CI file-lock flake. Tests never ran.
• macOS x64 TestBuild + AoT: AzDO job timed out at 2h30m because 4 unrelated Helix work items hung: NetAnalyzers.UnitTests.dll.16, StaticWebAssets.Tests.dll.10, StaticWebAssets.Tests.dll.15, dotnet-watch.Tests.dll.1. Our test partition (dotnet.Tests.dll.20) completed in 6m 2s with all assertions passing.

Recommendation

Bug doesn't reproduce. I'm marking this PR Ready for Review — the unskip stands and #52029 can stay closed. Happy to drop the diagnostic test-asset enrichment (extra Lib + async tests + stronger coverage.config) before merge if you'd rather keep the asset minimal; let me know.

cc @Youssef1313

[Copilot]

Pull request overview

Strengthens the existing dotnet test --coverage regression/diagnostic for #52029 by ensuring static managed instrumentation actually performs IL rewriting (via non-empty <ModulePaths><IncludeDirectories>) and by making the test asset contain real async state machines in both a referenced library and the test assembly itself. This makes the unskipped IncludeTestAssembly=true rows meaningful on Linux/macOS instead of being effectively no-ops.

Changes:

• Expanded the TestProjectSolutionWithCodeCoverage test asset with a new Lib project containing async patterns (Task.Yield, Task.Delay, IAsyncEnumerable) and added async MSTest methods that exercise it.
• Updated the coverage settings written by the CLI test to enable static managed instrumentation and to include the test project bin/<Configuration> directory recursively, preventing the instrumenter’s early short-circuit.
• Unskipped the IncludeTestAssembly=true cases and updated the expected test run summary counts (now 6 total tests, 1 failing).

Show a summary per file

File	Description
test/TestAssets/TestProjects/TestProjectSolutionWithCodeCoverage/TestProjectSolutionWithCodeCoverage.sln	Adds the new Lib project to the solution and configuration mappings.
test/TestAssets/TestProjects/TestProjectSolutionWithCodeCoverage/TestProject/TestProject.csproj	References Lib so coverage instrumentation and test execution traverse both assemblies.
test/TestAssets/TestProjects/TestProjectSolutionWithCodeCoverage/TestProject/Test1.cs	Adds async tests and an await foreach path to produce realistic async state machines in the test assembly.
test/TestAssets/TestProjects/TestProjectSolutionWithCodeCoverage/Lib/Lib.csproj	Introduces a class library project in the test asset (TFM via $(CurrentTargetFramework)).
test/TestAssets/TestProjects/TestProjectSolutionWithCodeCoverage/Lib/AsyncCalculator.cs	Implements async APIs designed to force IL rewriting by static instrumentation.
test/dotnet.Tests/CommandTests/Test/GivenDotnetTestBuildsAndRunsTestsWithArtifacts.cs	Unskips IncludeTestAssembly=true, writes richer coverage.config, and updates assertions for the new test count.

Copilot's findings

• Files reviewed: 6/6 changed files
• Comments generated: 0