現代中繼：如何模擬中繼進行單元測試

Question

我正在嘗試測試反應中繼現代容器，但遇到了這個問題。

TypeError: Cannot read property 'environment' of undefined

下面是測試代碼：

test('render component', () => {
  const tree = renderer.create(
    <User />,
  ).toJSON();

  expect(tree).toMatchSnapshot();
});

Answer 1

將以下內容添加到__mocks__文件夾。 然后在測試中添加jest.mock('react-relay'); 到需要中繼的單元測試。 這將模擬中繼並只留下要測試的組件。

 import React from 'react'; import PropTypes from 'prop-types'; const relayMock = jest.genMockFromModule('react-relay'); const relayChildContextTypes = { relay: PropTypes.object, }; const relayEnvironment = { lookup: jest.fn(), }; const relayContext = { relay: { environment: relayEnvironment, variables: {}, }, }; const relayFragmentProps = { relay: { environment: relayEnvironment, }, }; const relayRefetchProps = { relay: { environment: relayEnvironment, refetch: jest.fn(), }, }; const relayPaginationProps = { relay: { environment: relayEnvironment, hasMore: jest.fn(), loadMore: jest.fn(), isLoading: jest.fn(), }, }; relayMock.__relayEnvironment = relayEnvironment; relayMock.__relayFragmentProps = relayFragmentProps; relayMock.__relayRefetchProps = relayRefetchProps; relayMock.__relayPaginationProps = relayPaginationProps; const makeRelayWrapper = (relayProps) => ( (Comp) => { class HOC extends React.Component { getChildContext() { return relayContext; } render() { return <Comp {...this.props} {...relayProps}/>; } } HOC.childContextTypes = relayChildContextTypes; return HOC; } ); relayMock.QueryRenderer = jest.fn(() => React.createElement('div', null, 'Test')); relayMock.createFragmentContainer = makeRelayWrapper(relayFragmentProps); relayMock.createRefetchContainer = makeRelayWrapper(relayRefetchProps); relayMock.createPaginationContainer = makeRelayWrapper(relayPaginationProps); module.exports = relayMock;

Answer 2

您實際上根本不需要模擬環境變量。 我通常做的是添加：

export class User

到我要測試的類的類聲明。 （確保在同一類的連接版本上保持導出默認值）。

然后，我可以通過導入組件以首選方式測試組件，而無需像在我的測試中這樣的中繼：

 import { User } from '../User'

這消除了對模擬中繼的需要，您可以將 props 干凈地傳遞給組件。