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Question: How can I test BullMQ jobs with Jest in Node.js?


To test BullMQ jobs with Jest in Node.js, you need to follow these steps:

  1. Set up Jest in your project: First, make sure Jest is installed and configured properly in your project. If not, you can add it using npm or yarn:
npm install --save-dev jest


yarn add --dev jest
  1. Create BullMQ Jobs: Let's assume you have a simple BullMQ job called sendEmail:
const Queue = require('bullmq').Queue; const sendEmailQueue = new Queue('sendEmail'); sendEmailQueue.add('send', { email: '', message: 'Hello!' });
  1. Mock BullMQ: Because we don't want to actually send emails when running tests, use Jest to mock the BullMQ functionality. Here's how to do that:
jest.mock('bullmq', () => { return { Queue: jest.fn().mockImplementation(() => { return { add: jest.fn() }; }) }; });
  1. Write Tests: Now, you can write a test for any function that uses the sendEmail queue. If the function calls sendEmailQueue.add(), the mock implementation will be used instead of the real one:
const { sendEmail } = require('./sendEmail'); const { Queue } = require('bullmq'); test('sendEmail function should add a job to the queue', async () => { await sendEmail('', 'Hello!'); expect(Queue.mock.instances[0].add).toHaveBeenCalledWith('send', { email: '', message: 'Hello!' }); });

Remember, this is a basic example. In a real-world scenario, you might have more complex jobs and may need to adjust your mocks accordingly.

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