Apply structured assertion messages (RFC 012) to Assert.MatchesRegex / DoesNotMatchRegex

[Evangelink]

Continues the rollout of RFC 012 — Structured Assertion Messages by migrating Assert.MatchesRegex / Assert.DoesNotMatchRegex to the structured-message format. Follows the pattern established by previously migrated assertions (#8170, #8187, #8210, #8214) and the in-flight #8258 (StartsWith/EndsWith).

Output format

Assert.MatchesRegex(new Regex(""^foo""), ""hello""):

Assertion failed. Expected string to match the specified regular expression.

expected pattern: ""^foo""
actual:           ""hello""

Assert.MatchesRegex(new Regex(""^foo""), ""hello"")

Assert.DoesNotMatchRegex(new Regex(""world""), ""hello world"", ""value should not match""):

Assertion failed. Expected string to not match the specified regular expression.
value should not match

unexpected pattern: ""world""
actual:             ""hello world""

Assert.DoesNotMatchRegex(new Regex(""world""), ""hello world"")

Notes

• Adds MatchesRegexFailedSummary / DoesNotMatchRegexFailedSummary resource entries (XLF files regenerated via UpdateXlf).
• Removes the now-unused BuildUserMessageForPatternExpressionAndValueExpression helper from Assert.cs because the call-site is now reconstructed by FormatCallSiteExpression.
• StringAssert.Matches / StringAssert.DoesNotMatch are intentionally unchanged and continue to use FrameworkMessages.IsMatchFail / IsNotMatchFail.

Validation

• dotnet build src/TestFramework/TestFramework/TestFramework.csproj -c Debug — clean.
• dotnet test test/UnitTests/TestFramework.UnitTests/TestFramework.UnitTests.csproj -c Debug — 3535/3535 passed.

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

[Copilot]

Pull request overview

Rolls forward the RFC 012 “Structured Assertion Messages” migration by converting Assert.MatchesRegex and Assert.DoesNotMatchRegex to the structured, multi-line failure format and wiring new localized summary resources.

Changes:

• Migrated Assert.MatchesRegex / Assert.DoesNotMatchRegex failure paths to StructuredAssertionMessage + EvidenceBlock + call-site rendering.
• Added new FrameworkMessages.*FailedSummary resource entries and regenerated corresponding XLF entries.
• Removed the now-unused BuildUserMessageForPatternExpressionAndValueExpression helper from Assert.cs.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Assertions/Assert.Matches.cs	Converts regex assertions to structured assertion messages with evidence blocks and call-site formatting.
src/TestFramework/TestFramework/Assertions/Assert.cs	Removes unused user-message builder helper now that call-sites are formatted via FormatCallSiteExpression.
src/TestFramework/TestFramework/Resources/FrameworkMessages.resx	Adds MatchesRegexFailedSummary and DoesNotMatchRegexFailedSummary resource strings.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.cs.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.de.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.es.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.fr.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.it.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.ja.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.ko.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.pl.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.pt-BR.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.ru.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.tr.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.zh-Hans.xlf	Adds new trans-units for the two new summary resource keys.
src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.zh-Hant.xlf	Adds new trans-units for the two new summary resource keys.

Copilot's findings

• Files reviewed: 16/16 changed files
• Comments generated: 2

[Evangelink]

Review Summary — PR #8259: Structured assertion messages for Assert.MatchesRegex / DoesNotMatchRegex

This PR continues the RFC 012 rollout in a clean, consistent manner. The implementation faithfully mirrors the pattern established by prior migrations (#8170, #8187, #8210, #8214, #8258).

Dimension	Result	Severity
Algorithmic Correctness	✅ LGTM	—
Threading & Concurrency	✅ N/A (no shared state)	—
Security	✅ N/A	—
Public API & Binary Compatibility	✅ LGTM	—
Performance & Allocations	✅ LGTM	—
Cross-TFM Compatibility	✅ LGTM	—
Resource & IDisposable	✅ N/A	—
Localization & Resources	✅ LGTM — XLF files regenerated via the UpdateXlf automated build target	—
Test Completeness	⚠️ ISSUE	MODERATE
Code Structure	✅ LGTM	—
Naming & Conventions	✅ LGTM	—
Documentation Accuracy	✅ LGTM	—
Scope & PR Discipline	✅ LGTM	—

Notable design consistency

WithExpectedAndActual(patternText, actualText) is called in ReportAssertDoesNotMatchRegexFailed, storing the (unwanted) pattern as AssertFailedException.ExpectedText. This is consistent with how other DoesNot* methods (e.g. DoesNotContain, DoesNotStartWith) handle the same property in this codebase — the evidence block labels ("unexpected pattern:" / "actual:") provide the human-readable semantics.

Single finding

Test coverage gap (MODERATE): No unit tests were added for the new structured failure message paths. See the inline comment on line 163 of Assert.Matches.cs for details and recommendations.

Generated by Expert Code Review (on open) for issue #8259 · ● 14.5M

[Evangelink]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved. I merged origin/main, fixed the conflicts, regenerated the FrameworkMessages XLF files, and committed the merge resolution in 63e9c64.

[Evangelink]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved. I merged the latest origin/main, fixed the new conflicts, and committed the merge resolution in 246d348.

[Copilot]

Copilot's findings

Comments suppressed due to low confidence (1)

src/TestFramework/TestFramework/Assertions/Assert.Matches.cs:149

• Same issue as above: [DoesNotReturn] is not accurate because ReportAssertFailed(StructuredAssertionMessage) returns in AssertScope mode. Please remove the attribute (or ensure the method truly does not return).

    [DoesNotReturn]
    private static void ReportAssertDoesNotMatchRegexFailed(Regex pattern, string value, string? userMessage, string patternExpression, string valueExpression)
    {

• Files reviewed: 17/17 changed files
• Comments generated: 2