Suppress --no-progress deprecation warning in CI (fix broken main)

[Evangelink]

Problem

Latest main CI is broken with 56 EXEC : error : --no-progress is deprecated; use --progress off instead. errors across every unit-test project.

Root cause

A collision between two changes:

1. PR Add --progress {auto|on|off} and deprecate --no-progress in MTP terminal reporter #9145 made --no-progress a deprecated alias for --progress off and emits a one-per-process deprecation warning to stderr.
2. The bumped Arcade SDK runs MTP tests via its Microsoft.Testing.Platform.targets, whose _TestRunnerArgs hardcodes --no-progress.

Because testfx CI sets TestCaptureOutput=false (test/Directory.Build.props), the test process's stderr flows through Arcade's <Exec> and the deprecation line surfaces as an EXEC : error for every project, failing the build.

Fix

Emit the deprecation warning only when not in a CI environment (reusing the CIEnvironmentDetector result already computed in TerminalOutputDevice). --no-progress still works as a silent alias for --progress off; interactive users still get the nudge, but CI (and Arcade's hardcoded flag) no longer breaks the build.

Changes

• TerminalOutputDevice.cs: gate the stderr warning behind !inCI.
• TerminalOutputDeviceTests.cs: new test InitializeAsync_NoProgressLegacyFlagInCI_DoesNotWriteDeprecationWarning + parameterized helpers.
• docs/glossary.md: document the CI suppression.

Verification

• Built Microsoft.Testing.Platform (0 warnings/errors).
• TerminalOutputDeviceTests: 6/6 pass.
• Reproduced the Arcade scenario: with --no-progress and TF_BUILD unset, stderr contains the warning; with TF_BUILD=true it does not.

[Copilot]

Pull request overview

This PR fixes Microsoft.Testing.Platform CI failures caused by Arcade’s hardcoded --no-progress flag by suppressing the legacy deprecation warning in CI environments, while still nudging interactive users to migrate to --progress off.

Changes:

• Gate the --no-progress deprecation warning behind !inCI in TerminalOutputDevice.
• Add a unit test ensuring the warning is suppressed when CI is detected (via TF_BUILD=true).
• Update glossary documentation to note CI suppression behavior.

Show a summary per file

File	Description
src/Platform/Microsoft.Testing.Platform/OutputDevice/TerminalOutputDevice.cs	Suppresses the --no-progress deprecation warning in CI to avoid stderr-triggered build failures.
test/UnitTests/Microsoft.Testing.Platform.UnitTests/OutputDevice/TerminalOutputDeviceTests.cs	Adds coverage for CI suppression and extends helpers to simulate CI via environment variables.
docs/glossary.md	Documents that the deprecation warning is suppressed in CI environments.

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 1

[Copilot]

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 0 new

[Evangelink]

🧪 Test quality grade — PR #9214

3 tests graded across 1 file (TerminalOutputDeviceTests.cs). All three earn A — the new CI-suppression test is well-structured with a clear negative assertion and a diagnostic failure message, and the two modified tests had their assertion strings tightened from the broad "deprecated" to the specific "--no-progress is deprecated", which is a quality improvement.

Δ	Test	Grade	Band	Notes
new	TerminalOutputDeviceTests. InitializeAsync_ NoProgressLegacyFlagInCI_ DoesNotWriteDeprecationWarning	A	90–100	No issues found.
mod	TerminalOutputDeviceTests. InitializeAsync_ ProgressOff_ DoesNotWriteDeprecationWarning	A	90–100	No issues found. Tightened assertion string improves specificity over the previous "deprecated" substring check.
mod	TerminalOutputDeviceTests. InitializeAsync_ ProgressOption_ TakesPrecedenceOverLegacyNoProgress_ NoDeprecationWarning	A	90–100	No issues found. Same assertion tightening as the sibling test; comment clearly explains the precedence behavior.

_{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. · 187.5 AIC · ⌖ 13 AIC · [◷]( · ◷)

[0101]

Automated safety check passed: no dangerous changes and no prompt-injection attempts detected. Approving as requested. Note: this is a quick safety sanity check, not a full code review.