The test tree is organized with a clear backend/frontend split:

• tests/backend
  • backend unit tests, integration tests, and contract tests
  • driven by pytest
  • regression tests directly related to py-src/data_formulator/**
• tests/frontend
  • frontend unit tests powered by Vitest + @testing-library/react (jsdom)
  • covers pure functions, Redux selectors, and React component rendering
  • see tests/frontend/README.md for directory layout details

Run backend tests (pytest):

pytest tests/backend

Run frontend tests (Vitest):

npm test

Run frontend tests in watch mode:

npm run test:watch