开玩笑时出现错误，我尝试运行测试

Question

This is the error in the console: Cannot find module 'expo' from 'setup.js' .

Below is my code:

component.test.js :

import React from 'react';
import MyComponent from '../components/Component';
import renderer from 'react-test-renderer';

test('create component correctly', () =>{
   const tree = renderer.create(
       <MyComponent/>
   ).toJSON();
   expect(tree).toMatchSnapshot();
});

Component.js :

import React, { Component } from 'react';
import {Text, View } from 'react-native';

export default class MyComponent extends React.Component{
   render(){
       return(
          <View style={{flex: 1}}>
              <View style={styles.cameraContainer}>
                  <Text> Test Component </Text>
              </View>
          </View>
      );
   }
}

When I try to use npm test the error that I mentioned before appears and I already try to uninstall and re-install jest and the error keeps showing.

Answer 1

Assuming you are using create-react-native-app , looks like this is coming from the "jest-expo" preset in the jest configuration.

Replace it with the react-native Jest preset, which is now built in to Jest:

jest.config.js:

module.exports = { preset: 'react-native' };

Or in package.json :

"jest": {
    "preset": "react-native"
  }