问如何测试子组件根据父组件的状态进行渲染？

EN

describe('ParentComponent', () => {
    test('renders Child1 component when conditionMet is true', () => { 

      const parentMount = mount(<ParentComponent />);

      const param1 = "expected value";
      const param2 = true;    
      parentMount.instance().checkCondition(param1, param2); // results in Parent's state 'conditionMet' === 'true'

      //This is not working - the length of the Child1 component is always 0
      expect(parentMount.find(Child1)).toHaveLength(1);

      //This alternate option passes, but it's not testing the rendering of the component!
      expect(parentMount.text()).toMatch('Expected string renders from Child1'); 

    });
  });

class ParentComponent extends Component {
  constructor(props) {
    super(props);
    this.state = {
      conditionMet: false
    };
  }

  checkCondition = (param1, param2) => { 
  if (param1 === 'expected value' && param2 === true)
    {
       this.setState({conditionMet: true});
    } else {
       this.setState({conditionMet: false});
     }
     this.displayChildComponent();      
     }
  };

  displayChildComponent() {
    if (this.state.conditionMet) {
      return(
          <Child1 />
      )
    }
    else {
      return(
          <Child2 />
      )
    }
  }

  render() {
    return (
      <div className="parent-container">
        {this.displayChildComponent()}
      </div>
    );
  }
}