What are the best practices for testing React hooks with Testing Library?

What are the best practices for testing React hooks with Testing Library?

When testing React hooks with Testing Library, it's important to focus on the behavior of the hooks rather than their implementation. Here are some best practices:

1. Use the renderHook utility to test hooks in isolation.
2. Mock any dependencies to ensure your tests are focused.
3. Test the hook's return values and side effects.
4. Keep your tests readable and maintainable.

Can you give me an example of using renderHook?

Sure! Here's a simple example:

import { renderHook } from '@testing-library/react-hooks';
import { useMyHook } from './myHook';

test('should return expected value', () => {
  const { result } = renderHook(() => useMyHook());
  expect(result.current).toBe(expectedValue);
});

What should I do if my hook has side effects?

If your hook has side effects, you can use the act function from React Testing Library to ensure that all updates related to the side effects are processed. For example:

import { act, renderHook } from '@testing-library/react-hooks';

test('should handle side effects', () => {
  const { result } = renderHook(() => useMyHook());
  act(() => {
    result.current.triggerSideEffect();
  });
  expect(result.current.someValue).toBe(expectedValue);
});