Is there some way to test the inner implementation when response in Observable is 500 (Error occured)

Question

Here is the code below

@Output() hitCodeReturned = new EventEmitter<boolean>();

ngOnInit() {
  this.someService.method().subscribe(
  () => {
    // Some code here
  },
  ({ error }) => {
    if (condition equals true) {
      this.hitCodeReturned.emit(true);
    }
  }
);

}

The test should ensure that true will be emitted when response will return error with some body

Answer 1

yes, just use throwError operator in test

 //in jasmine/karma test
 //assuming that someService is a `mock`
    it('propagates hitCodeReturned', (done)=>{
  
        someService.and.return(throwError("here you can throw any kind of error"));
        component.hitCodeReturned().subscribe(code=>{
          expect(code).toBeTrue();
          done();
        });
        component.ngOnInit();
        
       
    }