Simple counter test

counter.spec.ts

describe('CounterComponent', () => {
  let component: CounterComponent;
  let fixture: ComponentFixture<CounterComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [CounterComponent]
    }).compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(CounterComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });
    
  it('should increment', () => {
    
      component.count();
      expect(component.counts).toBe(1);
      component.count();
      expect(component.counts).toBe(2);
    
  });

  it('should decrement', () => {
    
      component.counts = 5;
    
      component.subtruct();
      expect(component.counts).toBe(4);
      component.subtruct();
      expect(component.counts).toBe(3);
  });

  it('should reset', () => {
    
      component.counts = 5;
      component.subtruct();

  });

});