Add --ansi option for explicit ANSI control

[Copilot]

Summary

Adds a new --ansi <auto|on|off> CLI option to give users explicit control over ANSI escape sequence output. Fixes #5081.

Behavior

• --ansi auto (default): Auto-detect terminal capabilities (existing behavior when no option is passed).
• --ansi on|true|enable|1: Force ANSI output (including cursor movement) even when stdout is redirected, e.g. mytest.exe | Out-Host.
• --ansi off|false|disable|0: Disable ANSI output.
• --no-ansi: continues to work unchanged.
• When both --ansi and --no-ansi are specified, --ansi wins (documented in the help text).

Implementation notes

• New internal CommandLineOptionArgumentValidator helper exposes IsValidBooleanArgument / IsValidBooleanAutoArgument / IsOnValue / IsOffValue / IsAutoValue so future boolean and boolean+auto options (e.g. --no-progress) can reuse it.
• The --ansi value parsing in TerminalOutputDevice uses a private AnsiOverride enum scoped to that file. We considered promoting a generic ActivationMode (Auto/On/Off) enum into the CommandLine namespace but kept it local for now to avoid widening the public/internal surface for a single consumer; a follow-up can introduce a shared type once a second option (e.g. --no-progress) actually needs it.
• --no-ansi is intentionally left without deprecation/obsolescence metadata. The earlier prototype added obsolescence plumbing to CommandLineOption but it was reverted because the matching infrastructure was removed from main by Delete dead code #7734 as dead code, and reintroducing it for a single option felt out of scope. The help text for --ansi instead notes that --ansi wins over --no-ansi so users have a clear migration path.

Tests

• Unit tests for CommandLineOptionArgumentValidator and the updated TerminalTestReporterCommandLineOptionsProvider.
• New AnsiOptionTests acceptance tests covering on/off/auto behavior, the alias values, precedence vs --no-ansi, and invalid argument rejection.
• Updated MTP and MSTest --help / --info acceptance expectations to include the new option.

[nohwnd]

I need to go through the logic around use ansi and force ansi on the internal options. I am not clear on why we needed / need both options. so please wait for me.

[nohwnd]

just comments that you don't have to address.

[nohwnd]

^^^

[Evangelink]

Rebased onto current main from scratch (the prior branch was stale and had non-trivial conflicts). I dropped the AutoOnOff enum and the obsolescence-marker plumbing for --no-ansi so the change stays small (the obsolescence infrastructure was removed from main by #7734 as dead code, and reintroducing it for one consumer felt out of scope). Instead, --ansi maps straight to the existing internal AnsiMode enum:

• --ansi on|true|enable|1 → AnsiMode.ForceAnsi (fulfils Add --ansi option to force Ansi output #5081 — emits ANSI even when stdout is redirected)
• --ansi off|false|disable|0 → AnsiMode.NoAnsi
• --ansi auto (default) → current detection logic (LLM → NoAnsi, CI → SimpleAnsi, else → AnsiIfPossible)
• --no-ansi stays working as-is; any explicit --ansi <value> wins over it

Help text calls out that --ansi on includes cursor movement and recommends pairing with --no-progress for clean redirected output.

The branch went through 3 rounds with the expert reviewer; iterations addressed: (1) --ansi auto + --no-ansi precedence, (2) CI-deterministic auto test, (3) a precedence test that's also immune to LLM env-var leakage. Final regression guard uses --no-ansi --ansi on because ForceOn short-circuits both inCI and LLMEnvironmentDetector checks.

Acceptance tests need build.cmd -pack to run locally; I built Microsoft.Testing.Platform, the unit-tests project (864/864 pass) and the integration tests project (compiles cleanly).

[Copilot]

Pull request overview

This PR adds an explicit --ansi <auto|on|off> command-line option to control whether ANSI escape sequences are emitted by the terminal reporter, while keeping --no-ansi for backward compatibility. It also updates localization resources and acceptance tests so --help/--info output reflects the new option.

Changes:

• Add --ansi option (with auto|on/off aliases) and wire it into TerminalOutputDevice ANSI mode selection/precedence over --no-ansi.
• Introduce a reusable CommandLineOptionArgumentValidator helper and add unit tests for the validator and the terminal option provider.
• Update help/info acceptance-test expectations and add an integration test validating redirected-output behavior for --ansi.

Show a summary per file

File	Description
test/UnitTests/Microsoft.Testing.Platform.UnitTests/OutputDevice/Terminal/TerminalTestReporterCommandLineOptionsProviderTests.cs	Adds unit tests for --ansi option validation and presence.
test/UnitTests/Microsoft.Testing.Platform.UnitTests/CommandLine/CommandLineOptionArgumentValidatorTests.cs	Adds unit tests for the new boolean/auto argument validator helpers.
test/IntegrationTests/MSTest.Acceptance.IntegrationTests/HelpInfoTests.cs	Updates MSTest runner --help expectations to include --ansi.
test/IntegrationTests/Microsoft.Testing.Platform.Acceptance.IntegrationTests/HelpInfoTests.cs	Updates MTP --help and --info expectations to include --ansi.
test/IntegrationTests/Microsoft.Testing.Platform.Acceptance.IntegrationTests/HelpInfoAllExtensionsTests.cs	Updates “all extensions” help/info expectations to include --ansi.
test/IntegrationTests/Microsoft.Testing.Platform.Acceptance.IntegrationTests/AnsiOptionTests.cs	Adds integration tests validating --ansi behavior (esp. when stdout is redirected).
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.zh-Hant.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.zh-Hans.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.tr.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.ru.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.pt-BR.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.pl.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.ko.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.ja.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.it.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.fr.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.es.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.de.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.cs.xlf	Adds localized entries for --ansi description + invalid-argument message.
src/Platform/Microsoft.Testing.Platform/Resources/PlatformResources.resx	Adds TerminalAnsiOptionDescription and TerminalAnsiOptionInvalidArgument resources.
src/Platform/Microsoft.Testing.Platform/OutputDevice/TerminalOutputDevice.cs	Parses --ansi and applies precedence over --no-ansi to select AnsiMode.
src/Platform/Microsoft.Testing.Platform/OutputDevice/Terminal/TerminalTestReporterCommandLineOptionsProvider.cs	Declares --ansi and validates its argument via the new validator.
src/Platform/Microsoft.Testing.Platform/CommandLine/CommandLineOptionArgumentValidator.cs	Adds reusable helpers for auto/on/off argument validation.

Copilot's findings

• Files reviewed: 23/23 changed files
• Comments generated: 3

[Evangelink]

Closing in favor of #8493, which is a refreshed version of this PR (cleaner validator code using LINQ, refactored TerminalOutputDevice branch using CIEnvironmentDetector, and an additional acceptance test for the missing-argument case).