Assertions: Use expect() to assert the expected behavior.?

Short answer: Example: import { render, screen, fireEvent } from '@testing-library/react'; import MyComponent from './MyComponent'; test('renders the component and interacts', () => { render(<MyComponent />); const button = screen.getByText('Click me'); fireEvent.click(button); expect(screen.getByText('Clicked!')).toBeInTheDocument(); });

Example code

import { render, screen, fireEvent } from '@testing-library/react'; import MyComponent from './MyComponent'; test('renders the component and interacts', () => { render(<MyComponent />); const button = screen.getByText('Click me'); fireEvent.click(button); expect(screen.getByText('Clicked!')).toBeInTheDocument(); });

Real-world example (ShopNest)

ShopNest’s storefront is React: components for ProductCard, CartDrawer, and CheckoutForm, with hooks for local UI state.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.