Drop MSTest's VSTest bridge dependency on the MTP path

[Evangelink]

What

Complete Phase 6b of the native MTP integration work by making MSTest's Microsoft.Testing.Platform path native-only.

This follows:

• Native MTP integration for MSTest — RFC 018 + Phases 1–5 (opt-in native path) #9706 — RFC 018 + phases 1-2
• Native MTP framework for MSTest — Phases 3–5 (native filter/runsettings/context, opt-in) #9743 — phases 3-5
• Native MTP integration for MSTest (Phase 6a): native providers, config, resources #9748 — phase 6a (native path self-contained on the request/registration side, bridge still default)
• Simplify TestRunParameters argument validation with LINQ (PR #9748 follow-up) #9749 — small review follow-up

This PR is the final flip/removal step: MSTest no longer routes the MTP path through Microsoft.Testing.Extensions.VSTestBridge.

Changes

• Remove MSTestBridgedTestFramework from MSTest.TestAdapter.
• Stop gating MTP registration behind MSTEST_EXPERIMENTAL_NATIVE_MTP; MSTestTestFramework is now the only MTP test framework.
• Drop the MSTest.TestAdapter project reference to Microsoft.Testing.Extensions.VSTestBridge.
• Add the direct dependencies that used to flow transitively through the bridge:
  • Microsoft.Testing.Extensions.TrxReport.Abstractions
  • Microsoft.Testing.Extensions.Telemetry
  • Microsoft.TestPlatform.ObjectModel
• Rename BridgedConfiguration to PlatformServicesConfigurationAdapter.
• Update trim/discovery tests and comments to the native-only topology.

Validation

• build.cmd clean
• MSTestAdapter.UnitTests: 45/45
• MSTestAdapter.PlatformServices.UnitTests: 898/898
• build.cmd -pack clean; package validation clean
• MSTest acceptance high-signal slice green (RunsettingsTests, FilterTests, HelpInfoTests, TrxReportTests, ThreadingTests)
• Full MSTest acceptance: only the 3 pre-existing local NativeAOT failures remain
  • NativeAotTests_WillRunWithExitCodeZero (net8.0)
  • NativeAotTests_WillRunWithExitCodeZero (net10.0)
  • NativeAot_Smoke_Test

Those 3 failures are the same local trim-warning environment issue already observed before this PR; the focused trim regression tests were updated and pass on the native-only graph.

Notes

The package graph is now what we wanted from the beginning of this effort:

• removed: Microsoft.Testing.Extensions.VSTestBridge
• direct: Microsoft.Testing.Extensions.TrxReport.Abstractions, Microsoft.Testing.Extensions.Telemetry, Microsoft.TestPlatform.ObjectModel

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

[Copilot]

Pull request overview

This PR completes Phase 6b of the native Microsoft.Testing.Platform (MTP) integration for MSTest (RFC 018). It flips MSTest's MTP path to be native-only: MSTestTestFramework becomes the sole MTP test framework, the VSTest bridge framework and its opt-in gate are removed, and MSTest's MSTest.TestAdapter package no longer depends on Microsoft.Testing.Extensions.VSTestBridge. This finalizes the decoupling so MSTest plugs into MTP directly instead of round-tripping through the VSTest object model.

Changes:

• Remove MSTestBridgedTestFramework and the MSTEST_EXPERIMENTAL_NATIVE_MTP gating; MSTestTestFramework is now always used, and MSTestCapabilities implements only the native IMSTestTrxReportCapability.
• Swap the MSTest.TestAdapter project reference to Microsoft.Testing.Extensions.VSTestBridge for direct references to TrxReport.Abstractions, Telemetry, and an unconditional Microsoft.TestPlatform.ObjectModel.
• Rename BridgedConfiguration to PlatformServicesConfigurationAdapter, and update trim/discovery tests and code comments to the native-only topology.

Show a summary per file

File	Description
src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestBridgedTestFramework.cs	Deletes the now-unused VSTest bridge framework.
src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/TestApplicationBuilderExtensions.cs	Drops the env-var gate; always registers MSTestTestFramework; MSTestCapabilities implements only the native TRX capability.
src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/PlatformServicesConfigurationAdapter.cs	Renames BridgedConfiguration to PlatformServicesConfigurationAdapter.
src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestTestFramework.cs	Updates the field type to the renamed adapter and clarifies the class summary (removes opt-in remarks).
src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestFilterContext.cs	Comment update to describe the former bridge behavior in past tense.
src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestTestNodeConverter.cs	Comment updates referencing the bridge in past tense.
src/Adapter/MSTest.TestAdapter/VSTestAdapter/MSTestDiscoverer.cs	Comment update: internal constructor is used by the native framework.
src/Adapter/MSTest.TestAdapter/MSTest.TestAdapter.csproj	Replaces the VSTestBridge reference with direct TrxReport.Abstractions/Telemetry references and makes Microsoft.TestPlatform.ObjectModel unconditional.
test/IntegrationTests/MSTest.Acceptance.IntegrationTests/TrimTests.cs	Updates trimmer root assemblies (drops VSTestBridge, adds MSTest.TestAdapter) and comments for the Application Insights telemetry dependency.
test/IntegrationTests/MSTest.Acceptance.IntegrationTests/TestDiscoveryTests.cs	Comment update reflecting that MSTest natively leaves assemblyFullName/returnTypeFullName empty.

Review details

• Files reviewed: 10/10 changed files
• Comments generated: 0
• Review effort level: Medium

[github-actions]

Note

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Review Summary — PR #9755: Drop MSTest's VSTest bridge dependency on the MTP path

Clean, well-scoped PR that completes Phase 6b of the native MTP integration. The removal of MSTestBridgedTestFramework, the MSTEST_EXPERIMENTAL_NATIVE_MTP feature flag, and the bridge project reference are all consistent — no dangling references remain in production or test code.

Verdict Table

#	Dimension	Verdict	Notes
1	Algorithmic Correctness	✅ Pass	Registration logic simplified; single-path factory is correct
2	Threading & Concurrency	✅ Pass	CountdownEvent-based session guard unchanged
3	Exception Handling	✅ Pass	No changes to exception semantics
4	Resource Management	✅ Pass	IDisposable pattern unchanged
5	API Design & Contracts	✅ Pass	Public surface unchanged; AddMSTest signature intact
6	Performance & Allocation	✅ Pass	Removes dead-code Environment.GetEnvironmentVariable check on hot path
7	Cross-TFM / Platform	✅ Pass	ObjectModel now unconditional (UWP + netfx + net8+); UWP guard preserved on MTP-only refs
8	Backward Compatibility	✅ Pass	Experimental flag removed (never shipped publicly); native path was already the production path for anyone opting in
9	Public API Surface	✅ Pass	No new public API; PublicAPI.Unshipped.txt empty
10	Security	✅ Pass	No security-sensitive changes
11	Localization	✅ Pass	No new resources; existing .xlf files untouched
12	Test Quality	✅ Pass	Trim/discovery tests properly updated for the new topology
13	Documentation & Comments	⚠️ Minor	One stale comment in .csproj (see inline)
14	Naming Conventions	i️ Info	VSTestBridgedTestFrameworkSessionAlreadyCreatedErrorMessage resource still uses "Bridged" — cosmetic; renaming would churn 13 .xlf files for no functional gain
15	Code Duplication	✅ Pass	Bridge code deleted, not duplicated
16	Error Propagation	✅ Pass	Session-already-created error unchanged
17	Dependency Management	✅ Pass	Transitive deps made explicit correctly (TrxReport.Abstractions, Telemetry, ObjectModel)
18	Build & Project File	✅ Pass	Conditions and PrivateAssets settings are correct
19	Diagnostic & Observability	✅ Pass	Trace logger wiring unchanged
20	Scope Discipline	✅ Pass	Changes are tightly scoped to bridge removal
21	Style & Formatting	✅ Pass	Consistent with codebase conventions
22	TODO Policy	✅ Pass	Removed the untracked TODO from the bridge; no new TODOs added

One Minor Finding

The .csproj comment about Microsoft.TestPlatform.Filter.Source (lines 93–95) still uses present tense ("It flows in transitively via the VSTestBridge today") despite the bridge reference being removed in this PR. See inline suggestion.

Overall: Excellent, clean execution. No blocking or major issues. 👍

Comments that could not be inline-anchored

src/Adapter/MSTest.TestAdapter/MSTest.TestAdapter.csproj:95

MINOR — Stale comment (present tense about removed dependency)

This comment still says "It flows in transitively via the VSTestBridge today" — but the VSTestBridge reference was removed in this very PR. The ObjectModel comment just above (lines 87–90) was correctly updated to past tense; this one should match:

    <!-- The native Microsoft.Testing.Platform integration (TestingPlatformAdapter\MSTestFilterContext, guarded by
         !WINDOWS_UWP) parses VSTest filter expressi…

</details>

[github-actions]

🧪 Test quality grade — PR #9755

Grade	Test	Notes
B (80–89)	mod TestDiscoveryTests. DiscoverTests_ WithJsonOutput_ ProducesValidJsonDocumentWithExpectedFields	Comprehensive JSON coverage; split per-behavior (exit code, schema, display names) to ease failure diagnosis.
B (80–89)	mod TrimTests. Publish_ WithSourceGeneration_ DoesNotSurfaceMSTestOwnedTrimWarnings	Clear absence assertions; add an exit-code check before the warning scan to surface publish failures explicitly.
B (80–89)	mod TrimTests. Publish_ WithTestAdapter_ DoesNotSurfaceWarningsFromSuppressedSources	Well-commented regression test; add an exit-code check before the absence scan to surface publish failures explicitly.

_{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. Generated by the Grade Tests on PR (on open / sync) workflow. · 100.4 AIC · ⌖ 12.2 AIC · ⊞ 9.5K · [◷]( · ◷)