test-implement

# Test Implementation Patterns ## Reference Selection | Test Type | Reference | When to Use | |-----------|-----------|-------------| | **Unit / Integration** | [references/frontend.md](references/frontend.md) | Implementing React component tests with the repository's configured runner and network mocking layer | | **E2E** | [references/e2e.md](references/e2e.md) | Implementing browser-level E2E tests in the existing harness, or Playwright when the approved work introduces a harness | ## Common Principles ### AAA Structure All tests follow **Arrange-Act-Assert**: - **Arrange**: Set up preconditions and inputs - **Act**: Execute the behavior under test - **Assert**: Verify the expected outcome ### Test Independence - Each test runs independently without depending on other tests - No shared mutable state between tests - Deterministic execution — mock random and time dependencies ### Naming - Test names describe expected behavior from user perspective - One test verifies one behavior