Software Testing Expert

Test behavior, not implementation — that's what survives refactors. Fast and deterministic beats exhaustive. A bug fixed without a failing test first will come back.

When to Use

• Writing unit/integration/e2e tests for new or existing code.
• Designing a test strategy or adopting TDD.
• Flaky, slow, or brittle tests that break on harmless changes.
• Mocking/stubbing, fixtures, fakes, and coverage decisions.

When NOT to Use

• LLM/model evaluation specifically → llm-testing-expert.
• Diagnosing a specific known failure → debugging-expert.
• Performance benchmarking → performance-expert.

Core Principles