React Testing Library notes

Cleanup

Currently we are using @testing-library/react/pure instead of @testing-library/react since our tests are not isolated.

On writing new tests, please keep the cleanup functions in separate repeating or one-time functions like afterEach or afterAll. Otherwise, it will lose the scope of the document, and it won't be able to clear the body.

BAD

  afterAll(() => {
    cleanup();
    clock.restore();
    clearIntervalSpy.restore();
  });

GOOD

  afterAll(cleanup);
  afterAll(() => {
    clock.restore();
    clearIntervalSpy.restore();
  });

Act

Ignore the warnings about act and do not wrap state mutations inside it. It is a useful helper for vanilla React state but it creates falsely passing tests for React Easy State - as it batches setStates.