medium post updated describe

thing.2.spec.js

  describe('when the props change', () => {
    it('will publish the correct messages based on the prop', () => {
      // lets give the component a 'value' prop
      component = shallow(<Thing value={3} />);

      // lets update the component with the same prop
      component.setProps({ value: 3 });
      expect(PubSub.publish).lastCalledWith('thing.will.receive.props');
      // shouldComponentUpdate will return false
      // so componentWillUpdate() will not call
      expect(PubSub.publish).not.toHaveBeenCalledWith('thing.should.update');
      expect(PubSub.publish).not.toHaveBeenCalledWith('thing.will.update');
    });
  });