不確定如何為條件渲染的 ReactJS 組件編寫測試用例

Question

我的應用程序最初使用組件內的加載占位符呈現，5 秒后呈現不同的元素。 我想用笑話和酶來測試這個組件。

我的問題是，當我測試它和 console.log(wrapper.debug()) 時，它只顯示加載部分。

現在我的問題是如何對條件部分進行單元測試。

我的 App.js

import React,{useState, useEffect} from 'react';
import logo from './logo.svg';
import './App.css';

const App = () => {
  const [loading, setLoading] = useState(true);
  useEffect(()=>{
    setTimeout(() => {
      setLoading(false)
    }, 5000);
  },[])
  if(loading){
    return <span>loading....</span>
  }
  return (
    <div className="App">
      <header className="App-header">
        <img src={logo} className="App-logo" alt="logo" />
        <p>
          Edit <code>src/App.js</code> and save to reload.
        </p>
        <a
          className="App-link"
          href="https://reactjs.org"
          target="_blank"
          rel="noopener noreferrer"
        >
          Learn React
        </a>
      </header>
    </div>
  );
}

export default App;

我的 App.test.js

import React from "react";
import App from "./App";
import { shallow } from "enzyme";

describe("app component", () => {
  it("loading state", () => {
    const setState = jest.fn();
    const useStateMock = (initState) => [initState, setState];
    jest.spyOn(React, "useState").mockImplementation(useStateMock);
    jest.spyOn(React, "useEffect").mockImplementation(setState);
    const wrapper = shallow(<App />);
    const result = wrapper.find("#abc");
    result.simulate("click");
    wrapper.update();
    console.log(wrapper.debug());
    expect(setState).toHaveBeenCalledWith(false);
  });
});

Answer 1

您可以嘗試使用： jest.setTimeout(6000)

import React from "react";
import App from "./App";
import { shallow } from "enzyme";

describe("app component", () => {
  it("loading state", () => {
    const setState = jest.fn();
    const useStateMock = (initState) => [initState, setState];
    jest.spyOn(React, "useState").mockImplementation(useStateMock);
    jest.spyOn(React, "useEffect").mockImplementation(setState);
    const wrapper = shallow(<App />);
    const result = wrapper.find("#abc");
    result.simulate("click");
    wrapper.update();
    jest.setTimeout(6000)
    console.log(wrapper.debug());
    expect(setState).toHaveBeenCalledWith(false);
  })