How Can I Trust My Test Suite?
summary
Argues that code coverage can be misleading and demonstrates using PHPUnit coverage dashboards, Infection mutation testing, CRAP/cyclomatic complexity and churn analysis (with charmphp) to assess test quality. Shows a toy reactor example producing 5 mutants with an 80% mutation score (four killed, one escaped) to illustrate how coverage can miss dangerous bugs, and recommends property testing, focused tests on risky files, frequent small releases, and production monitoring.
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chapters (10)
- 0:00Trust in test suite
- 3:35Code coverage limits
- 7:14Cyclomatic complexity risks
- 11:53Code risk metrics
- 16:34Mutation testing
- 25:45Mutation workflow
- 26:50Property testing
- 30:18Frequent releases
- 33:29Test value for agility
- 35:18Q&A
