Question 1. What are the types of testing, and why are they used?

Unit Test

• Tests the smallest unit of code (function, component).
• Fast, easy to debug.
• Example: Verify that a React component renders correctly with given props.

Integration Test

• Ensures multiple modules work correctly together.
• Example: “Login form → API call → state update → UI reflects change.”

E2E Test (End-to-End)

• Simulates real user flows across the entire app.
• Uses tools like Cypress, Playwright, Selenium.
• Example: User can register → login → create a post successfully.

👉 Tests provide confidence, catch regressions, and improve reliability.

Question 2. What is React Testing Library (RTL)?

• A testing library focused on testing apps the way users interact with them.
• Avoids testing implementation details.

How it Works

1. render() renders the component in a virtual DOM.