javascript React/JestJS/Enzyme：如何测试 ref 函数？
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React/JestJS/Enzyme: How to test for ref function?
提问by user3142695
I'm running unit tests using Jest and Enzyme for this very simple component render():
我正在使用 Jest 和 Enzyme 为这个非常简单的组件运行单元测试render()：
render() {
return (<Input
id='foo'
ref={input => { this.refInput = input }}
/>)
}
it('should render Input', () => {
wrapper = shallow(<Component />)
expect(wrapper.find(Input)).toHaveLength(1)
})
I'm also using the coverage option of Jest and there I see, that the line
我也在使用 Jest 的覆盖选项，我看到，那条线
ref={input => { this.refInput = input }}
is not covered by my test. What do I have to do to get a full covered unit test for this sample component?
不在我的测试范围内。我必须做什么才能获得此示例组件的完整单元测试？
回答by Yangshun Tay
The ref is attached to an instance of the component hence you will have to use mountto get an instance of the component.
ref 附加到组件的实例，因此您必须使用它mount来获取组件的实例。
To test for the ref, add the following line
要测试ref，请添加以下行
expect(wrapper.instance().refInput).toBeTruthy();
Final result:
最后结果：
render() {
return (<Input
id='foo'
ref={input => { this.refInput = input }}
/>)
}
it('should render Input', () => {
const wrapper = mount(<Component />);
expect(wrapper.find(Input)).toHaveLength(1)
expect(wrapper.instance().refInput).toBeTruthy();
})
