thenReject() seems to not be working when returning Promise.resolve()/.reject()

[tom-mayer]

Hey

I have a test that looks like this:

it('should reject', async (done) => {
  when(mongoMock.start()).thenReject();
  try{
     await instance(mongoMock).start();
     console.log('fulfilled');
  }catch(err){
     console.log('rejected');
  }
  //....
});

This does not go into the catch block as I would expect. If I substitute the when line with

 when(mongoMock.start()).thenReturn(Promise.reject());

the code works as expected.

The start funciton of the mongo class looks something like this:

protected async startServices(): Promise<void> {
  try {
    // await some async stuff 
    return Promise.resolve();
  }catch(err){
    return Promise.reject();
  }
}

[NagRock]

Should be fixed in 2.3.2 version. thenReject method requires error to be passed to it. But now (in new version) it throws default error if none has been passed.

Thanks for reporting this.