How to run same test multiple times using jest

Question

I am using jest to run my test suite (with back-end as Node.js & express). Below is my code:

const puppeteer = require ('puppeteer');

test('testing login function', async () => {
    const browser = await puppeteer.launch ({  
        headless: true,
        args: ['--no-sandbox']
  });

    const page = await browser.newPage();

    await page.type('#username', 'admin');
    await page.type('#password', 'password');

    await page.click('login-button');

    await page.waitFor('.card');

    expect(texthead).toEqual('Welcome to webpage');

    await browser.close();
});

I am trying to run this same test multiple times at once, is there a way using it by jest, or maybe using other tools.

Answer 1

If you're looking for something that will essentially stress test a single test (looking for test flakiness like I was) then you could use the following one-liner in your terminal, which of course uses bash and Jest together.

for i in {1..100}; do npx jest <test_file> --silent || (echo 'Failed after $i attempts' && break); done

This specific command requires you to have npx installed and it uses the --silent option but you can change it as you please.

Answer 2

If you don't want tests run sequentially, you can use Promise.all. Here is a quick example of how you could refactor your code.

const runTheTest = async () => { 
  const browser = await puppeteer.launch ({
    headless: true, args: ['--no-sandbox'] 
  });
  .......
  return browser.close();
}

test('testing login function', async () => { 
  const testRuns = []
  for (let index = 0; index < NUMBER_OF_RUNS; index++) {
    testRuns.push(runTheTest())
  }
  return Promise.all(testRuns);
})