Console output swallowed with parallel execution

[KevinGrandon]

Do you want to request a feature or report a bug?

Bug report

What is the current behavior?

Parallel execution will cause subsequent parallel tests to swallow console output.

Add the following to any jsdom/node test:

for (let i = 0; i < 10; i++) {
    console.log('OUTPUT ' + i);
    await new Promise(resolve => setTimeout(resolve, 100));
}

Add multiple tests so parallel runs happen while this test is running.

What is the expected behavior?

You will see 10 lines of console logging in standard out.

Note: Running with CI=true fixes the issue

Please provide your exact Jest configuration

Standard jest environment, using the multi-project runner.

Run npx envinfo --preset jest in your project directory and paste the
results here

  System:
    OS: macOS Sierra 10.12.6
    CPU: x64 Intel(R) Core(TM) i7-7920HQ CPU @ 3.10GHz
  Binaries:
    Node: 8.11.1 - ~/.nvm/versions/node/v8.11.1/bin/node
    Yarn: 1.6.0 - ~/.nvm/versions/node/v8.11.1/bin/yarn
    npm: 5.6.0 - ~/.nvm/versions/node/v8.11.1/bin/npm

[KevinGrandon]

Note: this is a similar issue to #2441, but I've added additional details around how parallelism will cause this. I'm trying to reproduce on a smaller repo, but running into other bugs around the concurrency heuristic in Jest.

[hdpinto]

I noticed that console.log() gets swallowed but console.error() and console.warn() don't, particularly when using promises and making mocked API calls, if this is the same issue.

[tchakabam]

not sure if it helps anyone here, but am using Node v8.10.0, and while this wasn't working with Jest v21.x, after I upgraded to v23.1.0, it worked. This is regardless wether using parallel execution (on 25+ tests) or using the -i flag, or having --verbose or not. that being said, your issue might be a different one than the one I had. at least I can say that it "can" work :)

[SimenB]

I think this was fixed by #6871 (available in Jest 24), so optimistically closing

[github-actions]

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