如何在useEffect中用axios请求测试react组件？

Question

我已经在 useEffect 中对 react 功能组件进行了请求。 https://codesandbox.io/s/nifty-dew-r2p1d?file=/src/App.tsx

const App = () => {
  const [data, setData] = useState<IJoke | undefined>(undefined);
  const [isLoading, setIsLoading] = useState<boolean>(true);

  useEffect(() => {
    axios
      .get("https://v2.jokeapi.dev/joke/Programming?type=single")
      .then((res: AxiosResponse<IJoke>) => {
        setData(res.data);
      })
      .catch((err) => console.log(err))
      .finally(() => setIsLoading(false));
  }, []);

  return (
    <div className="App">
      {isLoading ? (
        <h2>Loading...</h2>
      ) : (
        <div className="info">
          <div className="info__cat">
            {data?.category ? `category: ${data.category}` : "bad category"}
          </div>
          <div className="info__joke">
            {data?.joke ? `joke: ${data?.joke}` : "bad data"}
          </div>
        </div>
      )}
    </div>
  );
};

如何用测试覆盖组件？我需要在请求之前、时间和之后测试状态。在这个上下文中如何模拟请求？

Answer 1

你无法通过 react-testing-library 在内部访问 state 和 setState。这是因为 RTL 希望您像用户一样测试您的组件。您应该尝试重现更改状态的一组操作。使用 react-testing-library 的 render 函数来渲染组件，将模拟的 state 和 setState 传递给该组件。使用 axios 中的 axiosMock 来模拟 axios。在这种方法中，您可以将模拟值检查为真实的本地状态。

import { render } from "react-testing-library";
import axiosMock from "axios";

这个 link 可能会有帮助：

async-axios-react-testing-library

Answer 2

选项 1. 使用 msw 通过在网络级别拦截请求来模拟。

选项 2。如果您不想安装任何包和设置，您可以使用 jest.spyOn(object, 'method').mockResolvedValueOnce() 为 axios.get() 方法创建一个模拟 resolved/rejected 值。

以下示例使用选项 2。

App.tsx:

import axios, { AxiosResponse } from 'axios';
import React, { useEffect, useState } from 'react';

interface IJoke {
  category: string;
  joke: string;
}

export const App = () => {
  const [data, setData] = useState<IJoke | undefined>(undefined);
  const [isLoading, setIsLoading] = useState<boolean>(true);

  useEffect(() => {
    axios
      .get('https://v2.jokeapi.dev/joke/Programming?type=single')
      .then((res: AxiosResponse<IJoke>) => {
        setData(res.data);
      })
      .catch((err) => console.log(err))
      .finally(() => setIsLoading(false));
  }, []);

  return (
    <div className="App">
      {isLoading ? (
        <h2>Loading...</h2>
      ) : (
        <div className="info">
          <div className="info__cat">{data?.category ? `category: ${data.category}` : 'bad category'}</div>
          <div className="info__joke">{data?.joke ? `joke: ${data?.joke}` : 'bad data'}</div>
        </div>
      )}
    </div>
  );
};

App.test.tsx:

import { App } from './App';
import axios, { AxiosResponse } from 'axios';
import { act, render, screen } from '@testing-library/react';
import '@testing-library/jest-dom/extend-expect';
import React from 'react';

describe('70450576', () => {
  afterEach(() => {
    jest.restoreAllMocks();
  });
  test('should render category and joke', async () => {
    const mAxiosResponse = {
      data: { category: 'smart', joke: 'sam' },
    } as AxiosResponse;
    jest.spyOn(axios, 'get').mockResolvedValueOnce(mAxiosResponse);
    render(<App />);
    expect(screen.getByText('Loading...')).toBeInTheDocument();
    expect(await screen.findByText('category: smart')).toBeInTheDocument();
    expect(await screen.findByText('joke: sam')).toBeInTheDocument();
  });
});

测试结果：

 PASS  examples/70450576/App.test.tsx (8.874 s)
  70450576
    ✓ should render category and joke (43 ms)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |   91.67 |    72.22 |      80 |   90.91 |                   
 App.tsx  |   91.67 |    72.22 |      80 |   90.91 | 19                
----------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        9.393 s, estimated 10 s

如何在useEffect中用axios请求测试react组件？

How to test react component with axios request in useEffect?

typescript

reactjs

jestjs

axios

react-testing-library