javascript - 检查 Jest 中功能组件的状态值

Question

我的组件有一个状态(特殊)，我如何在我的测试用例中检查这个状态值？

组件.jsx

      export function SearchProviders({ changeRoute }) {
             const [speciality, setspeciality] = useState("Hospital");
             // blah blah blah
      }

测试.jsx

const renderedModule = shallow(<SearchProviders />);
const speciality = renderedModule.find('#speciality');
speciality.simulate('change');
console.log(renderedModule.state('speciality'));

我尝试这样做，但它给我错误说 state() 只能在类组件上调用

Answer 1

这是基于@skyboyer的解释的单元测试解决方案。

不要测试 onInputChange 函数的实现细节。测试组件调用后有什么变化。

变化可能是文本内容、组件结构等。

index.tsx:

import React, { useState } from 'react';

export function SearchProviders({ changeRoute }) {
  const [speciality, setspeciality] = useState('Hospital');

  const onInputChange = () => {
    setspeciality(speciality.toUpperCase());
  };

  return (
    <div>
      <span>{speciality}</span>
      <input id="speciality" onChange={onInputChange}></input>
    </div>
  );
}

index.test.tsx:

import { SearchProviders } from './';
import React from 'react';
import { shallow, ShallowWrapper } from 'enzyme';

describe('60135675', () => {
  let wrapper: ShallowWrapper;
  beforeEach(() => {
    const props = { changeRoute: jest.fn() };
    wrapper = shallow(<SearchProviders {...props}></SearchProviders>);
  });
  it('should render', () => {
    expect(wrapper.exists()).toBeTruthy();
    expect(wrapper.find('span').text()).toBe('Hospital');
  });

  it('should handle input change', () => {
    wrapper.find('#speciality').simulate('change');
    expect(wrapper.find('span').text()).toBe('HOSPITAL');
  });
});

100%覆盖率的单元测试结果:

 PASS  stackoverflow/60135675/index.test.tsx (6.152s)
  60135675
    ✓ should render (11ms)
    ✓ should handle input change (2ms)

-----------|---------|----------|---------|---------|-------------------
File       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
-----------|---------|----------|---------|---------|-------------------
All files  |     100 |      100 |     100 |     100 |                   
 index.tsx |     100 |      100 |     100 |     100 |                   
-----------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        8.217s

源代码:https://github.com/mrdulin/react-apollo-graphql-starter-kit/tree/master/stackoverflow/60135675