javascript - Jasmine Test Error : Expected Spy XYZ to have been called

Question

I have a method in component.ts file, which is calling a service method. The code structure is like as following-

getDetails(){
  if(!alreadyCached){
     callLogFunction();
  }
  this.service.getData()
  .then(res => {
    //rest of the logic here
  })
  .catch(err=>{ //catch logic here })
}

My test block looks like this-

it('should call service.getData', ()=>{
  spyOn(service,'getData').and.returnValue(Promise.resolve([]);
  component.getDetails();
  fixture.whenStable().then(()=>{
    expect(service.getData).toHaveBeenCalled();
  }
}

Why am I getting error that expected spy getData to have been called It would be great if you can help me with testing then and catch block (how to write tests for them)

Thanks! :)

Answer 1

If you are trying to test that service.getData is called, as per your test name, you should write the test thus:

it('should call service.getData', ()=>{

  const getDataSpy = spyOn(service,'getData');

  component.getDetails();

  expect(getDataSpy).toHaveBeenCalled();
  
}

That way you have tested only that which you want to test, that the service method is called, without having other distractions