Types of test

• Unit tests // functions and calcs
• Integration test // services and external calls
• e2e tests // (end to end) tests, should test user interactions, components and pages

Example:

Our tests are written with "given-when-then" methodology

it(' should render component', async () => {
	// given a render component  
	render(<App/>)  

	// should show its content
	expect(screen.getByRole('heading').toBeInDocument();
});

Descriptions should follow:

describe('name of regarded test group', () => {})
it('what should happen when tests pass')

Run tests:

yarn test

For NextJs, which uses React, we make usage of jest and react-testing-library