...This is because jest will try to run puppeteer in parallel and the CI platform won't be able to handle all the parallel jobs in time. A fix to this is to run your test serially when in a CI environment. Users have discovered that running test serially in such environments can render up to 50% of performance gains. Writing integration test can be done using Puppeteer API but it can be complicated and hard because API is not designed for testing. Debugging tests can be hard sometimes and it is very useful to be able to pause tests in order to inspect the browser. Jest Puppeteer exposes a method jestPuppeteer.debug() that suspends test execution and gives you the opportunity to see what's going on in the browser.