breaking: remove CLI verbosity switch and re-use existing MTP output switch

[thomhurst]

Fixes #2457

[claude]

Claude finished @thomhurst's task —— View job

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Pull Request Review

Reviewing PR #3294: breaking: remove CLI verbosity switch and re-use existing MTP output switch

Review Tasks:

• Read project guidelines (CLAUDE.md)
• Analyze deleted files (VerbosityCommandProvider.cs, TUnitVerbosity.cs)
• Review modified VerbosityService.cs changes
• Check other modified files for consistency
• Evaluate code quality and best practices
• Assess potential bugs and performance impact
• Review security considerations
• Check test coverage implications
• Provide comprehensive feedback

Review Feedback

🎯 Overall Assessment: EXCELLENT

This is a well-executed refactoring that consolidates verbosity control by leveraging Microsoft.Testing.Platform's built-in --output switch instead of maintaining a custom --verbosity implementation. The change aligns with the project's philosophy of being "fast, modern, reliable, and enjoyable to use."

✅ Strengths

1. Code Quality & Best Practices

• Clean Architecture: Proper separation of concerns with smart defaults based on environment (Console vs IDE)
• Modern C# Usage: Follows project conventions with collection expressions, proper async patterns, and modern syntax
• Defensive Programming: Proper exception handling in IsConsoleEnvironment() with fallback to safe defaults
• Clear Naming: Methods like GetOutputLevel() and GetLogLevel() clearly indicate their purpose

2. Performance Considerations

• Reduced Complexity: Removes custom enum (TUnitVerbosity) and command provider, reducing code paths
• Efficient Environment Detection: Uses cached environment variables via EnvironmentVariableCache
• Smart Defaults: Avoids unnecessary output buffering in IDE environments while maintaining clean console output

3. User Experience Improvements

• Platform Integration: Better alignment with Microsoft.Testing.Platform standards
• Intelligent Defaults: Normal for console (less spam), Detailed for IDEs (real-time feedback)
• Backwards Compatibility: Maintains TUNIT_DISCOVERY_DIAGNOSTICS environment variable support

🔧 Technical Analysis

VerbosityService.cs Changes (TUnit.Engine/Services/VerbosityService.cs:83-124)

private static bool GetOutputLevel(ICommandLineOptions commandLineOptions, IServiceProvider serviceProvider)
{
    // Check for --output flag (Microsoft.Testing.Platform extension)
    if (commandLineOptions.TryGetOptionArgumentList("output", out var args) && args.Length > 0)
    {
        return args[0].Equals("Detailed", StringComparison.OrdinalIgnoreCase);
    }

    // Smart defaults: Normal for console (buffered output), Detailed for IDE (real-time output)
    return !IsConsoleEnvironment(serviceProvider);
}

This is excellent - the logic is clear and the defaults make sense for different environments.

Documentation Updates (docs/docs/reference/command-line-flags.md:92-99)
The updated documentation clearly explains the behavior and smart defaults, which is crucial for a breaking change.

🚨 Areas for Consideration

1. Breaking Change Communication

• ✅ Properly marked as breaking: in commit message
• ✅ Documentation updated to reflect new behavior
• ⚠️ Recommendation: Consider adding migration notes for users currently using --verbosity

2. Test Coverage

• Missing: No tests found for the new VerbosityService behavior
• Critical: The smart environment detection logic in IsConsoleEnvironment() should have unit tests
• Suggestion: Add tests for both console and IDE environment scenarios

3. Edge Cases

• Fallback Behavior: The try-catch in IsConsoleEnvironment() is good, but consider logging the exception at Debug level
• Case Sensitivity: The "Detailed" comparison uses proper OrdinalIgnoreCase - excellent

🔒 Security Assessment

• ✅ No security concerns identified
• ✅ No secrets or sensitive data exposed
• ✅ Proper exception handling prevents information leakage

🧪 Test Coverage Recommendations

High Priority:

1. Unit tests for VerbosityService constructor with different command line scenarios
2. Tests for GetOutputLevel() with various --output values
3. Tests for IsConsoleEnvironment() behavior with different service provider scenarios
4. Integration tests ensuring backwards compatibility with TUNIT_DISCOVERY_DIAGNOSTICS

Medium Priority:

1. End-to-end tests verifying actual output behavior in console vs IDE environments
2. Performance regression tests (though performance impact should be positive)

📋 Action Items

Before Merge:

1. ❗ Add unit tests for the new VerbosityService logic
2. ❗ Test backwards compatibility with existing environment variables
3. ✅ Verify no public API changes (this appears to be internal-only changes)

Post-Merge:

1. Monitor for user feedback on the breaking change
2. Consider adding analyzer rules to help users migrate from old patterns

🎉 Final Recommendation: APPROVE

This PR successfully achieves its goal of consolidating verbosity control while improving the user experience. The implementation is clean, follows project conventions, and maintains backwards compatibility where possible. The main concern is the lack of test coverage for the new logic, but the code quality is high and the change is well-documented.

Risk Level: Low (internal refactoring with good fallbacks)
Impact: Positive (better platform integration, cleaner codebase)

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