单元测试 React Native：NativeModules.RNViewShot 未定义。确保库已链接到本机端

Question

当我对应用程序中的各个组件运行一些单元测试时，我不断收到这个恼人的警告：

NativeModules.RNViewShot is undefined. Make sure the library is linked on the native side.

在我的根目录中，我运行'react-native link'并在控制台中看到：

rnpm-install info Platform 'ios' module react-native-view-shot is already linked
rnpm-install info Platform 'android' module react-native-view-shot is already linked
rnpm-install info Linking assets to ios project
rnpm-install info Linking assets to android project
rnpm-install info Assets have been successfully linked to your project

这里给出了什么 > ？

Platform: MacOS,
Editor: VSCode,
react: "16.4.0",
react-native: "0.54.2",
react-native-view-shot: "^2.4.0",

Answer 1

您需要为这个库进行模拟。

例如

1. 在app中创建目录__mocks __
2. 创建文件react-native-view-shot.js

3. 在该文件中，添加以下内容：

   jest.mock('react-native-view-shot', () => {
     return {
       // whatever function you want to mock, e.g capture: jest.fn()
     };
   });