How do I set up Jest for a Svelte project?

How do I set up Jest for a Svelte project?

To set up Jest for a Svelte project, you'll need to install Jest and some additional packages like babel-jest and svelte-jester. Would you like a step-by-step guide?

Yes, please provide the steps.

1. Install Jest and the necessary packages:

   npm install --save-dev jest svelte-jester babel-jest
   

2. Create a jest.config.js file in your project root with the following configuration:

   module.exports = {
     transform: {
       '^.+\.svelte$': 'svelte-jester',
       '^.+\.js$': 'babel-jest',
     },
     moduleFileExtensions: ['js', 'svelte'],
   };
   

3. Add a test script in your package.json:

   "scripts": {
     "test": "jest"
   }
   

4. Write your tests in a __tests__ directory or alongside your components.

What about testing Svelte components?

You can test Svelte components by importing them in your test files and using Jest's test and expect functions. Would you like an example?

Yes, that would be great!

Here's a simple example:

import MyComponent from '../MyComponent.svelte';
import { render } from '@testing-library/svelte';

test('it renders correctly', () => {
  const { getByText } = render(MyComponent);
  expect(getByText('Hello World')).toBeInTheDocument();
});