如何模拟反应路由器上下文

Question

我有相当简单的反应组件（如果路由处于活动状态，则添加“活动”类的链接包装器）：

import React, { PropTypes } from 'react';
import { Link } from 'react-router';

const NavLink = (props, context) => {
  const isActive = context.router.isActive(props.to, true);
  const activeClass = isActive ? 'active' : '';

  return (
    <li className={activeClass}>
      <Link {...props}>{props.children}</Link>
    </li>
  );
}

NavLink.contextTypes = {
  router: PropTypes.object,
};

NavLink.propTypes = {
  children: PropTypes.node,
  to: PropTypes.string,
};

export default NavLink;

我应该如何测试它？我唯一的尝试是：

import NavLink from '../index';

import expect from 'expect';
import { mount } from 'enzyme';
import React from 'react';

describe('<NavLink />', () => {
  it('should add active class', () => {
    const renderedComponent = mount(<NavLink to="/home" />, { router: { pathname: '/home' } });
    expect(renderedComponent.hasClass('active')).toEqual(true);
  });
});

它不起作用并返回TypeError: Cannot read property 'isActive' of undefined。它肯定需要一些路由器模拟，但我不知道如何编写它。

Answer 1

对于反应路由器 v4，您可以使用 <MemoryRouter>。以 AVA 和酶为例：

import React from 'react';
import PropTypes from 'prop-types';
import test from 'ava';
import { mount } from 'enzyme';
import sinon from 'sinon';
import { MemoryRouter as Router } from 'react-router-dom';

const mountWithRouter = node => mount(<Router>{node}</Router>);

test('submits form directly', t => {
  const onSubmit = sinon.spy();
  const wrapper = mountWithRouter(<LogInForm onSubmit={onSubmit} />);
  const form = wrapper.find('form');
  form.simulate('submit');

  t.true(onSubmit.calledOnce);
});

Answer 2

您可以将https://github.com/pshrmn/react-router-test-context 用于该目的

“创建一个复制 React Router 的 context.router 结构的伪上下文对象。这对于使用 Enzyme 进行浅层单元测试很有用。”

安装后，您将能够执行类似的操作

describe('my test', () => {
  it('renders', () => {
    const context = createRouterContext()
    const wrapper = shallow(<MyComponent />, { context })
  })
})

Answer 3

感谢@Elon Szopos 的回答，但我设法写了一些更简单的东西（遵循https://github.com/airbnb/enzyme/pull/62）：

import NavLink from '../index';

import expect from 'expect';
import { shallow } from 'enzyme';
import React from 'react';

describe('<NavLink />', () => {
  it('should add active class', () => {
    const context = { router: { isActive: (a, b) => true } };
    const renderedComponent = shallow(<NavLink to="/home" />, { context });
    expect(renderedComponent.hasClass('active')).toEqual(true);
  });
});

我必须将mount 更改为shallow，以免评估Link，这给了我与react-router TypeError: router.createHref is not a function 相关的错误。

我宁愿拥有“真正的”反应路由器，而不仅仅是一个对象，但我不知道如何创建它。

Answer 4

测试依赖于上下文的组件可能有点棘手。我所做的是编写一个我在测试中使用的包装器。

您可以在下面找到包装器：

import React, { PropTypes } from 'react'

export default class WithContext extends React.Component {
  static propTypes = {
    children: PropTypes.any,
    context: PropTypes.object
  }

  validateChildren () {
    if (this.props.children === undefined) {
      throw new Error('No child components were passed into WithContext')
    }
    if (this.props.children.length > 1) {
      throw new Error('You can only pass one child component into WithContext')
    }
  }

  render () {
    class WithContext extends React.Component {
      getChildContext () {
        return this.props.context
      }

      render () {
        return this.props.children
      }
    }

    const context = this.props.context

    WithContext.childContextTypes = {}

    for (let propertyName in context) {
      WithContext.childContextTypes[propertyName] = PropTypes.any
    }

    this.validateChildren()

    return (
      <WithContext context={this.props.context}>
        {this.props.children}
      </WithContext>
    )
  }
}

在这里你可以看到一个示例用法：

  <WithContext context={{ location: {pathname: '/Michael/Jackson/lives' }}}>
    <MoonwalkComponent />
  </WithContext>

  <WithContext context={{ router: { isActive: true }}}>
    <YourTestComponent />
  </WithContext>

它应该可以正常工作。