测试父组件中子组件的按钮

Question

我从三天后才开始进行测试和搜索，如何解决我的问题。希望你能帮助我..我有一个父组件：

import React from 'react';
import './Subscribe.scss';
import Button from '../../Components/Button/Button';

class Subscribe extends React.Component {
    state = {
        user: {
            firstName: '',
            pseudo:'',
            email: '',
            password:''
        }
    }

handleChange = (e) => {
    this.setState({
        user: {...this.state.user, [e.target.name]: e.target.value}
    }, () => console.log(this.state))
}

onSubmit = (e) => {
    //  e.preventDefault()
    console.log("you've clicked")
    //todo
}
    render() {
        return(
            <form className='subscribe' id='subscriptionForm'>
                <label htmlFor='firstName'>Prénom :</label>
                    <input
                        data-testid='inputString'
                        type='text'
                        name='firstName'
                        onChange={this.handleChange}
                        value={this.state.user.firstName}
                    />

                <label htmlFor='pseudo'>Pseudo :</label>
                    <input
                        data-testid='inputString'
                        type='text'
                        name='pseudo'
                        onChange={this.handleChange}
                        value={this.state.user.pseudo}
                    />
                <label htmlFor='email'>Email :</label>
                    <input
                        data-testid='inputString'
                        type='email'
                        name='email'
                        onChange={this.handleChange}
                        value={this.state.user.email}
                    />
                <label htmlFor='password'>
                    password :
                </label>
                <Button id='submitSubscription' text='Go go !' onSubmit={this.onSubmit}/>
                <Button text='Annuler'/>
            </form>
        )
    }
}

export default Subscribe;

子组件：

import React from "react";

const Button = (props) => {
    return (
        <button type="button" onClick={props.onClick}>{props.text}</button>
    )
}
Button.displayName = 'Button'
export default Button

我想测试一下，但是没有用...

我的测试：

import React from 'react';
import { shallow, mount } from 'enzyme';
import Subscribe from './Subscribe.js';
import Button from "./../../Components/Button/button.js"


describe('<LogIn />', () => {
    it('Should call onSubmit on subscribe component when button component is clicked and allow user to subscribe ', () => {
        // Rend le composant et les enfants et renvoie un wrapper Enzyme
        const wrapper = mount(<Subscribe />);
        // Trouve la première balise bouton
        const button = wrapper.find("#submitSubscription");
        // Récupère l'instance React du composant
        const instance = wrapper.instance();
        // Ecoute les appels à la fonction on Submit
        jest.spyOn(instance, "onSubmit");
        button.simulate('click');
        expect(instance.onSubmit).toHaveBeenCalled();
    })

评论是我尝试过的。答案仍然是Expected number of calls: >= 1 Received number of calls: 0我也愿意通过反应测试来尝试，因此我开始尝试任何帮助。

提前感谢！

Answer 1

工作示例（您可以通过单击Tests选项卡旁边的Browser选项卡运行测试）：

此示例使用一些es6 syntax，因此，如果您不熟悉，请阅读以下内容：

Object Destructuring

Spread syntax

Arrow Function Expressions (Fat Arrow/Lamba Functions) - Implict Returns
• components / Button / Button.js

---

import React from "react";

const Button = props => (
  <button
    style={{ marginRight: 10 }}
    type={props.type || "button"}
    onClick={props.onClick}
  >
    {props.text}
  </button>
);

Button.displayName = "Button";

export default Button;

components / Subscribe / Subcribe.js

import React, { Component } from "react";
import Button from "../Button/Button";
// import './Subscribe.scss';

const initialState = {
  user: {
    firstName: "",
    pseudo: "",
    email: "",
    password: ""
  }
};

class Subscribe extends Component {
  state = initialState;

  handleChange = ({ target: { name, value } }) => {
    // when spreading out previous state, use a callback function
    // as the first parameter to setState
    // this ensures state is in sync since setState is an asynchronous function
    this.setState(
      prevState => ({
        ...prevState,
        user: { ...prevState.user, [name]: value }
      }),
      () => console.log(this.state)
    );
  };

  handleCancel = () => {
    this.setState(initialState);
  };

  handleSubmit = e => {
    e.preventDefault();
    this.props.onSubmit(this.state);
  };

  render = () => (
    <form
      onSubmit={this.handleSubmit}
      className="subscribe"
      id="subscriptionForm"
    >
      <label htmlFor="firstName">Prénom :</label>
      <input
        data-testid="inputString"
        type="text"
        name="firstName"
        onChange={this.handleChange}
        value={this.state.user.firstName}
      />
      <br />
      <label htmlFor="pseudo">Pseudo :</label>
      <input
        data-testid="inputString"
        type="text"
        name="pseudo"
        onChange={this.handleChange}
        value={this.state.user.pseudo}
      />
      <br />
      <label htmlFor="email">Email :</label>
      <input
        data-testid="inputString"
        type="email"
        name="email"
        onChange={this.handleChange}
        value={this.state.user.email}
      />
      <br />
      <label htmlFor="password">password :</label>
      <input
        data-testid="inputString"
        type="password"
        name="password"
        onChange={this.handleChange}
        value={this.state.user.password}
      />
      <br />
      <br />
      <Button type="button" text="Annuler" onClick={this.handleCancel} />
      <Button id="submitSubscription" type="submit" text="Soumettre" />
    </form>
  );
}

export default Subscribe;
components / Subscribe / __ tests __ / Subscribe.test.js

（我传入了一个onSubmit道具来模拟它，我希望可以调用它。这是一个较常见的测试用例，而不是针对React的测试事件回调实现，强制您不必要地监视类字段。通过针对prop（或状态更改或某些辅助操作）进行测试，我们已经介绍了回调是否有效！）

import React from "react";
import { mount } from "enzyme";
import Subscribe from "../Subscribe.js";

const onSubmit = jest.fn();

const initProps = {
  onSubmit
};

describe("<LogIn />", () => {
  it("Should call onSubmit on subscribe component when button component is clicked and allow user to subscribe ", () => {
    const wrapper = mount(<Subscribe {...initProps} />);
    const spy = jest.spyOn(wrapper.instance(), "handleSubmit"); // not necessary
    wrapper.instance().forceUpdate(); // not necessary

    wrapper.find("button[type='submit']").simulate("submit");

    // alternatively, you could simply use:
    // wrapper.find("form").simulate("submit");

    expect(spy).toHaveBeenCalledTimes(1); // not necessary
    expect(onSubmit).toHaveBeenCalledTimes(1);
  });
});
index.js

import React from "react";
import { render } from "react-dom";
import Subscribe from "./components/Subscribe/Subscribe";
import "./styles.css";

const onSubmit = formProps => alert(JSON.stringify(formProps, null, 4));

render(
  <Subscribe onSubmit={onSubmit} />,
  document.getElementById("root")
);