Unify ApplicationStateGuard across copies (#9316)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)

[Amaury Levé (Evangelink)]

Fixes#9316. Updates the Platform and Adapter ApplicationStateGuard.Unreachable() copies to return UnreachableException, matching the TestFramework and Analyzer copies. All four projects already include the shared UnreachableException polyfill/global using, so no copy needed to stay on InvalidOperationException; Ensure() continues to throw InvalidOperationException. Adds source-copy comments pointing to the Platform canonical copy.

[Copilot]

Pull request overview

This PR addresses #9316 by aligning the behavior of the duplicated ApplicationStateGuard.Unreachable() helpers across Platform, Adapter, TestFramework, and Analyzers so they consistently return UnreachableException (while Ensure() continues throwing InvalidOperationException). It also adds comments intended to document the intentional source-copy pattern across these layered projects.

Changes:

• Switch ApplicationStateGuard.Unreachable() in Platform and Adapter copies to return UnreachableException for consistency with TestFramework and Analyzers.
• Add “source-copy / keep in sync” comments to all four copies, pointing at the Platform file as canonical.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Internal/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Platform/Microsoft.Testing.Platform/Helpers/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.
src/Analyzers/MSTest.Analyzers/Helpers/ApplicationStateGuard.cs	Adds source-copy sync comment referencing the canonical Platform copy.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/ApplicationStateGuard.cs	Changes Unreachable() to return UnreachableException; adds source-copy sync comment.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[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.

#	Dimension	Verdict
17	Documentation Accuracy	🟢 1 NIT

✅ 21/22 dimensions clean.

• Documentation — canonical Platform file's sync comment is self-referential (points to itself)

Notes on key dimensions checked:

• Cross-TFM Compatibility ✅ — UnreachableException polyfill in src/Polyfills/UnreachableException.cs (guarded #if !NETCOREAPP) is glob-included by all four affected projects, so the type change compiles on net462, netstandard2.0, and all UWP/WinUI targets.
• Backward Compatibility ✅ — Unreachable() is internal in all four classes; no public API surface changed.
• Test Coverage ✅ — No existing test catches InvalidOperationException from a path routed through ApplicationStateGuard.Unreachable(). The one test that uses Unreachable() in the adapter unit tests (TestMethodRunnerTests.cs:399) uses it as an unreachable lambda, not in a catch assertion.
• Algorithmic Correctness ✅ — UnreachableException (System.Diagnostics.UnreachableException) is the canonical type for "should never execute" guards; the type change is semantically correct and does not weaken any invariant.

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 8

[Copilot]

Copilot's findings

• Files reviewed: 20/20 changed files
• Comments generated: 4

[Amaury Levé (Evangelink)]

🧪 Test quality grade — PR #9329

3 test methods graded (all modified) across 3 files. Distribution: 2 × C, 1 × A. Both C-grade tests use the broad Assert.Throws<Exception> / Assert.ThrowsAsync<Exception> catch required by cross-assembly polyfill constraints — the rubric mechanically flags this as High → C ceiling; the A-grade test avoids the broad-catch pattern entirely and scores cleanly.

Δ	Test	Grade	Band	Notes
mod	ConfigurationExtensionsTests. ConfigurationExtensions_ TestedMethod_ ThrowsArgumentNullException	C	70–79	Assert.Throws(Exception) (High → C ceiling) is intentional — follow-up FullName check makes it specific.
mod	StopPoliciesServiceTests. RegisterOnMaxFailedTestsCallbackAsync_ ThrowsIfNotTestHost	C	70–79	Assert.ThrowsAsync(Exception) (High → C); narrowed by type-name check; foreach over 2 roles could be [DataRow].
mod	ApplicationStateGuardTests. Unreachable_ ReturnsUnreachableException	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. · 495 AIC · ⌖ 12.9 AIC · ⊞ 43.7K · [◷]( · ◷)