clean-output.md

Test Output Cleanliness

Principle: Test output should be clean and focused on test results, not cluttered with user-facing messages.

User-facing progress messages (emojis, status indicators, formatting) should never appear in test output as they:

• Make test output noisy and difficult to read
• Obscure actual test failures and important information
• Create inconsistent output between test runs
• Interfere with CI/CD log parsing and analysis

Enforcing Clean Test Output

The project enforces clean test output through:

1. Silent Verbosity by Default: TestContext uses VerbosityLevel::Silent to suppress all user-facing messages
2. Test-Specific Output Utilities: Use TestUserOutput::wrapped_silent() for clean test output
3. No User Messages in Tests: Tests should focus on verifying behavior, not producing user output

Best Practices

✅ Use Silent Verbosity in Tests

// ✅ Good: Uses silent verbosity by default
let context = TestContext::new();

// ✅ Good: Explicit silent output for API tests
let output = TestUserOutput::wrapped_silent();

❌ Avoid User-Facing Output in Tests

// ❌ Bad: Allows user-facing progress messages
let output = TestUserOutput::wrapped(VerbosityLevel::Normal);

// ❌ Bad: User output appears in test stderr
user_output.progress("⏳ Processing..."); // This will show in test output!

Testing User Output Components

When testing user output functionality itself:

#[test]
fn it_should_format_progress_message_correctly() {
    // Capture output in test buffers, don't let it reach stderr
    let test_output = TestUserOutput::new(VerbosityLevel::Normal);
    test_output.output.progress("⏳ Processing...");

    // Verify the message format in buffers
    let stderr = test_output.stderr();
    assert!(stderr.contains("⏳ Processing..."));
}

Why This Matters

Clean test output ensures:

• Readable Results: Developers can quickly identify failing tests
• Reliable CI/CD: Automated systems can parse test output correctly
• Professional Appearance: Test output looks polished and focused
• Debugging Efficiency: Important error messages aren't buried in noise

Remember: If you see user-facing messages (emojis, progress indicators) in test output, it indicates a testing infrastructure issue that should be fixed.