Error: Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL. - observable angular6

I try to check an observable function, using angular6. I get this error:

Error: Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL.

While I defined:

That is the test: (service.getSomthing is returning a new Observable)

it('test', (done) => {
    varToAssert = ....
    service.getSomthing(1).subscribe(()=>{
        //do something...

        expect(service.var).toEqual(varToAssert);

        done();
  });
}