Test case for stuudent component

students.component.spec.ts

  it('should set Error message when getUserDetails() is errored out', () => {
    expect(component.err_msg).toBeUndefined();
    spyOn(component._userService, 'getUserDetails').and.returnValue(throwError('Error'));
    const ele = fixture.debugElement.nativeElement.querySelector('#usr-1');
    ele.click();
    expect(component.err_msg).toBe('Error while loading User Details');
  });