Illustrative Pull-Request Description

Teaching fixture: This is an example review request. It does not represent an actual hosted pull request or merge request.

Title

Make quality-summary threshold handling explicit and testable

Problem and Intent

The quality-summary implementation combined the threshold contract and state aggregation in one loop. This made the supported threshold policy and intended preservation evidence hard to identify during review. The change makes those responsibilities explicit without changing the output shape.

Change

• Validates slowThresholdMs as a finite, non-negative input.
• Uses a named helper to count each quality state.
• Preserves a legacy implementation only as a characterization-test fixture.
• Adds deterministic summary and threshold tests; retains the existing polling, timeout, retry, and controlled-terminal-error tests as regression evidence.

Evidence

• npm run check
• npm test — deterministic tests with no application-runtime network dependency or real sleeps
• Characterization comparisons over no observations, an equality boundary, and mixed/repeated endpoints

Risks and Limits

• The characterization tests record representative observed behaviour only; they do not establish complete equivalence over all inputs.
• The legacy implementation remains solely for instructional comparison and should not become a second production path.
• The change does not address any new configuration or retry policy.

Suggested Review Focus

1. Is the threshold equality policy explicit and covered?
2. Are invalid-input and retry-failure semantics controlled and safe to expose?
3. Is the test suite testing observable behaviour rather than helper implementation details?
4. Does the diff stay within the declared scope?