jest-mock-fs

Node's fs mock for jest.

APIs Implemented

• fs.readFileSync
• fs.readdirSync
• fs.writeFileSync
• fs.readFile
• fs.readdir
• fs.writeFile
• fs.stat
• fs.unlink
• fs.mkdir
• fs.rmdir

Setup

Step 1: Install library

npm i --save-dev jest-mock-fs

Step 2: Create a mock and re-export library Inside your tests/__mocks__/fs.js

const fs = require('jest-mock-fs');
module.exports = fs;

Step 3: Add mock Inside your tests/example.test.js

jest.mock('fs');

View Full example.test.js file

const fs = require('fs');
jest.mock('fs');

test('should return content', async () => {
  // This will not create an actual file in your file system
  fs.writeFileSync('test.txt', 'test');
  const content = fs.readFileSync('test.txt', 'utf-8');
  expect(content).toBe('test');
});