在初始化后开玩笑更改模拟

Question

初始化测试后，我希望在测试中更改模拟数据。但当我试图改变它时，它并没有改变.我试图使用“clearAllMocks()”或使用jest.spy，但是没有任何改变。

• 当我说改变时，我的意思是‘isTablet’数据将改变

初始化会影响根项目上的许多其他测试。

jest-modules-mock.js

jest.mock('react-native-device-info', () => ({ isTablet: jest.fn() }));

组件

Welcome.tsx

const deviceType: BgImageByDevice = isTablet() ? 'tablet' : 'mobile';
export default ({ devices }: Welcome): ReactElement => {
const blabla = devices[deviceType]
}

试验

Welcome.test.tsx

const devices = {
    tablet: 'tablet',
    mobile: 'mobile',
  },

describe('<Welcome />', () => {

    test('devices should be mobile', () => {
      jest.doMock('react-native-device-info',() => ({  isTablet: () => false }))
      const Welcome = require('./Welcome').default
      const welcomeShallow = shallow(<Welcome devices={devices} />);
      const imageUrl = welcomeShallow.props().source.uri;
      expect(imageUrl).toBe(devices.mobile);
    });

    test('devices should be tablet', () => {
      jest.doMock('react-native-device-info',() => ({  isTablet: () => true }))
      const Welcome = require('./Welcome').default
      const welcomeShallow = shallow(<Welcome devices={devices} />);
      const imageUrl = welcomeShallow.props().source.uri;
      expect(imageUrl).toBe(devices.tablet);
    });
}

Answer 1

可以使用模拟文件更改模拟的值。您可以创建和导出一个模拟函数，您可以在测试中导入该函数，并更改实现或返回值。下面是这个过程的一个例子。

__mocks__\react-native-device-info.js

export const isTablet = jest.fn();

Welcome.test.js

import { shallow } from "enzyme";
import Welcome from "../Welcome";
import { isTablet } from "../__mocks__/react-native-device-info";

const devices = {
  tablet: 'tablet',
  mobile: 'mobile',
};

describe('<Welcome />', () => {
  test('devices should be mobile', () => {
    isTablet.mockReturnValue(false);
    const welcomeShallow = shallow(<Welcome devices={devices} />);
    // Your assertions go here
  });

  test('devices should be tablet', () => {
    isTablet.mockReturnValue(true);
    const welcomeShallow = shallow(<Welcome devices={devices} />);
    // Your assertions go here
  });
});