React Testing: Unit Testing React and E2E Testing

Define unit testing as validating small chunks of code, such as functions or React components, in isolation to ensure each feature works correctly and to cover all cases with tests.

Set up a vitest testing environment for React with React Testing Library and jsdom. Install dev dependencies, configure vitest, and write a basic describe/it test.

Test simple functions and helpers by organizing unit tests with nested describes for the range function, importing from utils.js, and validating results with expect.

Learn to test a simple react component using the react testing library by rendering with props, locating elements by data test id, and asserting text content for default messages.

Test a pagination component's rendering and click behavior with React Testing Library, covering total, limit, current page, and select page, plus user-event interactions and call assertions.

Explore the differences between mock and spy in unit tests, using a pagination example with a range function to isolate external dependencies and verify behavior rather than internal values.

Explore testing a useState-based username component with React Testing Library, focusing on rendering default empty text, updating state via button click and input typing, and avoiding state mocking.

Test useEffect and API calls in React by fetching tags with Axios, rendering via a test id, and validating with Testing Library; compare MSW server mocks with Axios spies.

Test a simple custom hook with renderHook from the Testing Library, verify initial count, initialize with a value, and validate increment behavior using act.

Explains testing a complex custom hook Usefetch that fetches data with axios from a url and returns loading, error, and response, including mocking axios and renderHook with async act.

Learn to test a real React project's context provider, reducers, and API calls with mocks, using React Testing Library for add, update, and remove todo actions.

Test the header component within a todos context by wrapping it with a provider, simulate typing and pressing enter to trigger add todo, and verify the function is called.

Learn how to test a React footer component using a todos context, validating visibility with and without todos, counting items left, and ensuring filter links update the active filter.

learn to implement a custom render in react testing to wrap components with multiple providers like redux, react query, and theme provider, and reuse test utilities for cleaner tests.

Explore unit testing a real React to-do component, covering rendering with the provider, mocking update and remove callbacks, toggling completion, editing, and focusing the edit input.

Test the main component by rendering with a todos context, mocking child components to simulate isolation, and verify props, toggle all behavior, and visibility with and without todos.

Learn how to test setTimeout in React using fake timers, advance timers by time, and wrap state updates in act for fast, reliable unit tests.

Explore testing Redux reducers in a React app using Redux toolkit, focusing on state with isLoading, error, and data, synchronous actions like set error, and async thunks: pending and fulfilled.

Learn to test Redux-connected React components by wrapping with a provider and a configured store, mocking Axios fetch calls, and validating post data and errors.

Explore end-to-end testing concepts, including intent testing on a real website, and compare its pros and cons with unit testing to improve overall website stability.

End-to-end test a todo app with Cypress, including setup, base URL, API interception, and verifying rendering, filtering, adding, editing, and deleting todos.

Celebrate completing the react testing course and mastering unit and e2e testing. Apply what you learned by testing your own project thoroughly and fixing mistakes for continued growth.