Mocking Promise

Implementation

// myModule.js

// Function that returns a Promise
export const fetchData = () => {
  return new Promise((resolve, reject) => {
    // Some asynchronous operation
    setTimeout(() => {
      resolve('Mocked Data');
    }, 1000);
  });
};

Test

import { fetchData } from './myModule';

jest.mock('./myModule'); // Automatically mocks the entire module

test('should mock the return value of fetchData', async () => {
  // Set the mocked return value
  fetchData.mockResolvedValue('Mocked Data');

  // Your test code that uses fetchData
  const result = await fetchData();

  // Assertions
  expect(result).toBe('Mocked Data');
});