--detectOpenHandles prints nothing, just hangs

🐛 Bug Report

When I run my test suite I get one of these 2 messages:

A worker process has failed to exit gracefully and has been force exited. This is likely caused by tests leaking due to improper teardown. Try running with --runInBand --detectOpenHandles to find leaks.

Jest did not exit one second after the test run has completed. This usually means that there are asynchronous operations that weren’t stopped in your tests. Consider running Jest with --detectOpenHandles to troubleshoot this issue.

For one, I think the mention of --runInBand in the first message is probably not necessary. But in any case, when I start running jest with --detectOpenHandles, I get no output, jest just hangs after finishing the tests.

Expected behavior

I would expect detectOpenHandles to give me actionable output.

envinfo

$ npx envinfo --preset jest
npx: installed 1 in 1.775s

  System:
    OS: macOS 10.15.2
    CPU: (4) x64 Intel(R) Core(TM) i7-7660U CPU @ 2.50GHz
  Binaries:
    Node: 10.18.0 - ~/.nvm/versions/node/v10.18.0/bin/node
    Yarn: 1.21.1 - /usr/local/bin/yarn
    npm: 6.13.6 - ~/.nvm/versions/node/v10.18.0/bin/npm
  npmPackages:
    jest: ^25.1.0 => 25.1.0

Issue Analytics

State:
Created 4 years ago
Reactions:147
Comments:54 (1 by maintainers)

Top GitHub Comments

91reactions

Prestaulcommented, Mar 13, 2020

I’m seeing the same issue. I’m not asking for help debugging my code, I’m pointing out a “concrete problem in jest”. In some code bases, when running jest with --runInBand --detectOpenHandles, as recommended by the CLI, the tests complete with no reported issues and jest hangs.

I have not been able to isolate a minimal reproduction, but this does not mean the issue isn’t real. Unless this is expected behavior, please reopen in acknowledgement that this is clearly affecting users.

76reactions

iyo-bemoorecommented, Mar 19, 2020

this solves it “test”: “jest --watch --runInBand --detectOpenHandles”