Javascript 玩笑窥探功能
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/42430368/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Jest spy on functionality
提问by Munsterberg
I am swapping to Jest from Mocha, and I'm wondering if there is a way to spy on a React method. For example, let's say I have the following method in my component (ignore the sdklibrary, it just constructs a jQuery Ajax call):
我正在从 Mocha 切换到 Jest，我想知道是否有办法监视 React 方法。例如，假设我的组件中有以下方法（忽略sdk库，它只是构造了一个 jQuery Ajax 调用）：
getData() {
sdk.getJSON('/someURL').done(data => {
this.setState({data});
});
}
Using Sinon I would test this by spying on the prototype like so:
使用Sinon，我将通过监视原型来测试这一点，如下所示：
it('should call getData', () => {
sinon.spy(Component.prototype, 'getData');
mount(<Component />);
expect(Component.prototype.getData.calledOnce).to.be.true;
});
This would ensure code coverage without mocking the method. Is there similar functionality in Jest?
这将确保代码覆盖率而不模拟方法。Jest 中是否有类似的功能？
EDIT: Also, if this functionality doesn't exist, what is the next best strategy for testing API calls?
编辑：此外，如果此功能不存在，那么测试 API 调用的下一个最佳策略是什么？
采纳答案by Andreas K?berle
回答by Denis Rybalka
Actually you can use jest.spyOn jest.spyOn
其实你可以使用 jest.spyOn jest.spyOn
If method is called when component created use:
如果在创建组件时调用方法，请使用：
import { mount } from 'enzyme';
describe('My component', () => {
it('should call getData', () => {
const spy = jest.spyOn(Component.prototype, 'getData');
mount(<Component />);
expect(Component.prototype.getData).toHaveBeenCalledTimes(1)
});
})
or if you have it in your DOM and method use bindyou can use:
或者如果你在你的 DOM 中拥有它并且方法 use bind你可以使用：
import { shallow } from 'enzyme';
describe('My component', () => {
it('should call getData', () => {
const wrapper = shallow(<Component />);
const instance = wrapper.instance()
const spy = jest.spyOn(instance, 'getData');
wrapper.find('button').simulate('click')
expect(spy).toHaveBeenCalledTimes(1)
});
})
回答by Nahush Farkande
You could go for the new spyOnmethod or the following should also work fine.
您可以采用新spyOn方法，或者以下方法也应该可以正常工作。
it('should call getData', () => {
Component.prototype.getData = jest.fn(Component.prototype.getData);
expect(Component.prototype.getData).toBeCalled();
});
回答by Wallysson Nunes
I'm using Jest with React 16.8 - This worked for me:
我在 React 16.8 中使用 Jest - 这对我有用：
it("lifecycle method should have been called", () => {
jest.spyOn(RedirectingOverlay.prototype, 'componentWillUnmount');
jest.spyOn(RedirectingOverlay.prototype, 'componentDidMount');
const wrapper = mount(<RedirectingOverlay message="Hi There!"/>);
expect(RedirectingOverlay.prototype.componentDidMount).toHaveBeenCalledTimes(1)
wrapper.unmount()
expect(RedirectingOverlay.prototype.componentWillUnmount).toHaveBeenCalledTimes(1)
})
Also using:
还使用：
"enzyme": "^3.6.0""jest": "23.5.0""enzyme-adapter-react-16": "^1.5.0"
"enzyme": "^3.6.0""jest": "23.5.0""enzyme-adapter-react-16": "^1.5.0"
