Support placeholders in --report-trx-filename

[Evangelink]

Resolves #5364.

The --report-trx-filename argument now supports placeholders provided by the existing artifact naming service (ArtifactNamingHelper):

Placeholder	Description
{pname}	Test application name (file name of the current test app, without extension)
{pid}	Process ID
{asm}	Entry assembly name
{tfm}	Target framework moniker (e.g. net9.0)
{time}	Timestamp (yyyy-MM-dd_HH-mm-ss.fffffff)

Example:

dotnet test <name>.sln -- --report-trx --report-trx-filename "test_results_{tfm}_{pid}.trx"

This fixes the long-standing issue where running the same --report-trx-filename value for every project in a solution produced a single TRX overwritten by every test project (the last one wins).

Implementation notes

• ArtifactNamingHelper and TargetFrameworkParser are linked into the TrxReport project (mirroring the HangDump extension).
• {pname} uses Path.GetFileNameWithoutExtension(_testApplicationModuleInfo.GetCurrentTestApplicationFullPath()) instead of Process.ProcessName so users get the test app name rather than dotnet.
• {pid} uses IEnvironment.ProcessId to avoid both the Process.GetCurrentProcess() banned-API rule and the CA1416 browser-platform warning.
• Placeholder resolution happens before the existing ReplaceInvalidFileNameChars so any unsafe characters in resolved values (e.g. parentheses, spaces) are still sanitized.
• Backward compatible: filenames without {...} placeholders are passed through unchanged.
• Existing CLI validation (.trx suffix, no path separators) is unchanged — placeholders never contain / or \, and the user still provides the literal .trx suffix.
• The --report-trx-filename description in ExtensionResources.resx documents the supported placeholders. XLF files were regenerated via msbuild /t:UpdateXlf.

Tests

5 new unit tests added in TrxTests.cs covering:

• {pname} and {pid} resolution
• Unknown placeholders preserved as-is
• Plain filename without placeholders unchanged (backward compat)
• {time} resolved from the injected IClock
• Invalid characters in resolved values are sanitized

All 144 Trx-related unit tests pass on net462/net472/net8.0/net9.0.

[Copilot]

Pull request overview

Adds placeholder support to the --report-trx-filename option (e.g., {pname}, {pid}, {asm}, {tfm}, {time}), reusing the existing ArtifactNamingHelper (already used by HangDump). This resolves the issue where running the same --report-trx-filename across multiple test projects in a solution overwrote a single TRX file.

Changes:

• In TrxReportEngine, resolve placeholders before ReplaceInvalidFileNameChars via a new ResolveTrxFileNamePlaceholders helper.
• Link ArtifactNamingHelper.cs and TargetFrameworkParser.cs into the TrxReport project.
• Update the resource description and corresponding XLF files (marked needs-review-translation); add 5 unit tests covering placeholder resolution, unknown placeholders, plain filenames, {time}, and sanitization of invalid characters from resolved values.

Show a summary per file

File	Description
src/Platform/Microsoft.Testing.Extensions.TrxReport/TrxReportEngine.cs	Adds ResolveTrxFileNamePlaceholders and invokes it before invalid-char replacement.
src/Platform/Microsoft.Testing.Extensions.TrxReport/Microsoft.Testing.Extensions.TrxReport.csproj	Links shared ArtifactNamingHelper.cs and TargetFrameworkParser.cs (mirrors HangDump).
src/Platform/Microsoft.Testing.Extensions.TrxReport/Resources/ExtensionResources.resx	Updates option description to document supported placeholders.
src/Platform/Microsoft.Testing.Extensions.TrxReport/Resources/xlf/ExtensionResources.*.xlf (14 locales)	Regenerated source text; targets marked needs-review-translation.
test/UnitTests/Microsoft.Testing.Extensions.UnitTests/TrxTests.cs	Adds 5 unit tests covering placeholder resolution scenarios.

Copilot's findings

• Files reviewed: 17/17 changed files
• Comments generated: 0

[Evangelink]

Review Summary — PR #8223: Support placeholders in --report-trx-filename

The implementation is clean and well-structured. The placeholder resolution correctly reuses ArtifactNamingHelper, the #if NET guard for GeneratedRegex is in place, ReplaceInvalidFileNameChars is applied after resolution, and backward compatibility is preserved. The five new unit tests are good. Two findings below.

Dimension	Verdict	Severity
Documentation Accuracy ({pname} label)	ISSUE	NIT
Test Completeness ({asm} / {tfm} coverage)	ISSUE	MODERATE
All other dimensions	LGTM	—

Finding 1 — Documentation: {pname} labelled "process name"

The resx description says {pname} (process name) but the code returns Path.GetFileNameWithoutExtension(GetCurrentTestApplicationFullPath()), which is the test app's module filename — not Process.ProcessName. Under dotnet test those differ (the latter is "dotnet"). The PR description itself calls this out as an intentional choice. The help text should say "test application name" instead.

Finding 2 — Test Completeness: no tests for {asm} and {tfm}

{asm} is resolved via Assembly.GetEntryAssembly()?.GetName().Name (with an "unknown" fallback) and {tfm} tries TargetFrameworkAttribute then RuntimeInformation.FrameworkDescription. Both code paths go untested. Consider adding tests — even simple ones that assert the resolved value is non-empty — so any regression in the reflection-based resolution is caught.

Generated by Expert Code Review (on open) for issue #8223 · ● 11.9M

[Copilot]

Copilot's findings

• Files reviewed: 18/18 changed files
• Comments generated: 2

[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 into this branch and fixed the conflict in TrxReportEngine.cs while preserving placeholder expansion behavior for --report-trx-filename.

Addressed in commit ae77a454b.

[RussKie]

Awesome, thanks! When will this change be GA?

[Evangelink]

I don't get have an exact date, there is quite some work I'd like to queue and I want to give some time for dogfooding.