argument of type observable is not assignable spyOn(http, 'get').and.callFake code example

Example: jasmine spyon argument of type is not assignable to parameter of type 'prototype'

const service = TestBed.get(GAService);
spyOn(service , "sendException").and.returnValue(Promise.resolve(true));

// do some stuff that is expected to invoke GAService.sendException

expect(service.sendException).toHaveBeenCalled();