使用 Jest 和 React Hooks 库测试 React Hooks 状态

Question

然后，我的导航组件将在侧边栏中切换状态以及打开和关闭菜单，然后尝试在代码覆盖范围中获取此通道。当我登录测试时，我的状态始终显示为未定义。不知道如何在这里解决这个问题。

组件.js：

const Navigation = (props) => {
  const {
    classes,
    ...navProps
  } = props;

  const [anchorEl, setanchorEl] = useState(null);
  const [sidebarOpen, setsidebarOpen] = useState(false);

  const toggleSidebar = () => {
    setsidebarOpen(!sidebarOpen);
  };

  const toggleMenuClose = () => {
    setanchorEl(null);
  };

  const toggleMenuOpen = (event) => {
    setanchorEl(event.currentTarget);
  };

  return (
    <Fragment>
     <Button
          onClick={toggleMenuOpen}
        />
      <SideMenu
        toggleSidebar={toggleSidebar}
      >
       <Menu
          onClose={toggleMenuClose}
        >
      </SideMenu>
    </Fragment>
  );
};

export default Navigation;

测试.js：

import { renderHook, act } from '@testing-library/react-hooks';

// Components
import Navigation from './navigation';

test('sidebar should be closed by default', () => {
    const newProps = {
        valid: true,
        classes: {}
    };

    const { result } = renderHook(() => Navigation({ ...newProps }));
    expect(result.current.sidebarOpen).toBeFalsy();
});

Answer 1

这里的作者react-hooks-testing-library。

react-hooks-testing-library不是用于测试组件并询问内部钩子状态以断言其值，而是用于测试自定义反应钩子并与钩子的结果进行交互，以确保其行为符合您的预期。例如，如果您想提取一个useMenuToggle看起来像这样的钩子：

export function useMenuToggle() {
  const [anchorEl, setanchorEl] = useState(null);
  const [sidebarOpen, setsidebarOpen] = useState(false);

  const toggleSidebar = () => {
    setsidebarOpen(!sidebarOpen);
  };

  const toggleMenuClose = () => {
    setanchorEl(null);
  };

  const toggleMenuOpen = (event) => {
    setanchorEl(event.currentTarget);
  };

  return {
    sidebarOpen,
    toggleSidebar,
    toggleMenuClose,
    toggleMenuOpen
  }
}

然后你可以用以下方法测试它renderHook：

import { renderHook, act } from '@testing-library/react-hooks';

// Hooks
import { useMenuToggle } from './navigation';

test('sidebar should be closed by default', () => {
    const newProps = {
        valid: true,
        classes: {}
    };

    const { result } = renderHook(() => useMenuToggle());
    expect(result.current.sidebarOpen).toBeFalsy();

    act(() => {
        result.current.toggleSidebar()
    })

    expect(result.current.sidebarOpen).toBeTruthy();
});

但一般来说，当钩子仅由单个组件和/或在单个上下文中使用时，我们建议您简单地测试该组件并允许通过它来测试钩子。

为了测试你的Navigation组件，你应该看看react-testing-library。

import React from 'react';
import { render } from '@testing-library/react';

// Components
import Navigation from './navigation';

test('sidebar should be closed by default', () => {
    const newProps = {
        valid: true,
        classes: {}
    };

    const { getByText } = render(<Navigation {...newProps} />);
    
    // the rest of the test
});