Originally posted by **DominicVonkPON** October 30, 2023
If you encounter a problem with Jest where the tests are not running due to the fake timers, it could be because MongoDB memory server relies on nextTick. To resolve this issue, you should avoid faking the nextTick function. By allowing the natural behavior of nextTick, you should be able to run the tests successfully with Jest.
```javascript
jest.useFakeTimers({
doNotFake: ['nextTick'], // do not fake nextTick behavior for mongo in memory
});
```
Discussed in https://github.com/nodkz/mongodb-memory-server/discussions/823