Skip to main content
Version: 0.20.6

Jest

Global Hooks Not Executed or Executed in Wrong Order

If you use Jest's global hooks like before*() and after*() that do no reside inside a describe-block you may run into the following issues:

  • Hooks are not executed at all
  • Hooks are executed in wrong order

The solution is to stop using global hooks and do your setup inside a describe-block. Please also consult Jest's docs for a detailed explanation.

/*
* DO NOT DO THIS!
*/
beforeAll(() => console.log('1 - beforeAll')); // won't work reliably
afterAll(() => console.log('1 - afterAll')); // won't work reliably
beforeEach(() => console.log('1 - beforeEach')); // won't work reliably
afterEach(() => console.log('1 - afterEach')); // won't work reliably

it('', () => console.log('1 - test'));

/*
* DO THIS INSTEAD
*/
describe('Scoped / Nested block', () => {
beforeAll(() => console.log('2 - beforeAll')); // works
afterAll(() => console.log('2 - afterAll')); // works
beforeEach(() => console.log('2 - beforeEach')); // works
afterEach(() => console.log('2 - afterEach')); // works

it('', () => console.log('2 - test'));

describe('More deeply scoped / nested block', () => {
beforeAll(() => console.log('3 - beforeAll')); // works
afterAll(() => console.log('3 - afterAll')); // works
beforeEach(() => console.log('3 - beforeEach')); // works
afterEach(() => console.log('3 - afterEach')); // works

it('', () => console.log('3 - test'));
});
});

Termination Error

Jest sometimes has problems terminating correctly. If this happens, you can see the following error message:

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.

As described in the error message Jest has problems stopping because of some processes which are still running. This can cause problems in your CI/CD pipeline because your pipeline can't continue after getting this error.

A solution is to force Jest to stop. For this case Jest provides the --forceExit flag:

npx jest --config ./test/jest.config.ts --forceExit