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description: Testing philosophy, Vitest/Playwright, coverage, and mocking
alwaysApply: true
---

Testing standards and tooling for the project.

## Testing philosophy
- Every meaningful code change should include appropriate test coverage.
- New files, functions, and methods should receive comprehensive test coverage where relevant.
- Definition of done includes tests passing.

## Required test layers
Use the appropriate mix of:
- unit tests
- integration tests
- component tests
- e2e tests where relevant

## Tooling defaults
- Use Vitest for unit and integration testing unless explicitly directed otherwise.
- Use Playwright for end-to-end testing.
- Use Testing Library patterns for UI/component tests where appropriate.

## Coverage expectations
- Maintain a minimum of 85% coverage per app/package.
- Coverage should include:
  - happy paths
  - edge cases
  - error cases

## Mocking standards
- Do not create duplicate mocks.
- Prefer centralized, reusable mocks, fixtures, and test factories.
- Integration tests should prefer realistic boundaries and minimal mocking.
- Unit tests may use mocks where appropriate, but shared mocks should be reused rather than redefined ad hoc.

## Quality standards
- Tests should be readable, deterministic, and isolated.
- Avoid brittle tests coupled to implementation details.
- Temporary test omissions are allowed only when explicitly acknowledged, but the work is not complete until the full test expectation is satisfied.
- Where practical, include accessibility-oriented testing for components and flows.