Jest: Jest hangs on invalid expectation(s)

[another-guy]

TL;DR The issue is specific to Node 10.0.0; Try upgrading to 10.1.0 or above.

🐛 Bug Report

If my there is at least one expectation in my unit test that is not fulfilled at test time, the entire test suite "hangs" instead of reporting a failed ("red") test.

(On contrary, If all my expectations are fulfilled at test time, the tests does not seem to hang.)

To Reproduce

The following test code is an example.

describe(`Demo`, () => {
  it(`Should Fail, not Hang`, () => {
    expect(1).toEqual(2);
  });
});

Run Jest from Git Bash/CMD, observe the following output:

$ yarn test
yarn run v1.6.0
(node:3316) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.
$ jest -i

 RUNS  __tests__/3-1-single-array-multiple-stacks.spec.ts

Software/Package Versions:

jest: 22.4.3
ts-jest: 22.4.5

$ node --version
v10.0.0

$ npm --version
6.0.0

$ npm --version
6.0.0

$ tsc --version
Version 2.8.3

Expected behavior

The test should be reported as failing.

Run npx envinfo --preset jest

$ npx envinfo --preset jest
npx: installed 1 in 5.897s

  System:
    OS: Windows 10
    CPU: x64 Intel(R) Core(TM) i5-3317U CPU @ 1.70GHz
  Binaries:
    Yarn: 1.6.0 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 6.0.0 - ~\AppData\Roaming\npm\npm.CMD

[rickhanlonii]

This seems configuration specific, can you push a repo?

[another-guy]

@rickhanlonii you can take a look at it here. (Please notice the branch -- repro).

Thanks for quick turnaround.

[rickhanlonii]

@another-guy hm, this did not hang for me:

[another-guy]

@rickhanlonii thank you for looking into it. I should try to rollback from Node.js 10.0.0 to whatever I had day before yesterday and re-check. Things seemed to be working jest a few days ago.

[SimenB]

It hangs when I use Node 10

[SimenB]

It does _not_ hang on node 10.1.0, though. Maaaaybe related to https://github.com/nodejs/node/pull/20266?

[another-guy]

@SimenB I confirm the upgrade resolved the issue. Thanks a ton!

$ node --version
v10.1.0

$ yarn test                                                                                                       
yarn run v1.6.0                                                                                                   
(node:2392) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use 
the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.                                       
$ jest -i                                                                                                         
(node:4552) ExperimentalWarning: The fs.promises API is experimental                                              
(node:4552) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use 
the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.                                       
 FAIL  __tests__\3-1-single-array-multiple-stacks.spec.ts                                                         
  Demo                                                                                                            
    × Should Fail, not Hang (13ms)                                                                                

  ● Demo › Should Fail, not Hang                                                                                  

    expect(received).toEqual(expected)                                                                            

    Expected value to equal:                                                                                      
      2                                                                                                           
    Received:                                                                                                     
      1

      1 | describe(`Demo`, () => {
      2 |   it(`Should Fail, not Hang`, () => {
    > 3 |     expect(1).toEqual(2);
      4 |   });
      5 | });
      6 |

      at Object.it (__tests__/3-1-single-array-multiple-stacks.spec.ts:3:15)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        2.523s
Ran all test suites.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.