使用Jest测试React Native应用程序

Testing React Native apps with Jest

本文关键字:Native 应用程序 React 测试 Jest 使用      更新时间:2023-09-26

我一直在努力让Jest使用我的react原生项目,但运气不佳。似乎大多数线程都是被黑客入侵的解决方案,以使事情正常运行,而我似乎无法克服我面临的最后一个障碍。

问题

我在尝试运行以下代码时遇到以下错误。如果我在jessupport/env.js文件中模拟反应,我可以克服错误,但显然我不能使用任何结构(如AsyncStorage)来实际测试我的代码(因为我只有模拟的功能)。

问题

有人对如何解决这个问题有什么建议吗?

在这个阶段,我愿意尝试任何事情,包括放弃所有与测试相关的东西,然后再试一次。如果是这样的话,我需要一些指导方针来遵循,因为React Native文档中关于Jest的内容已经过时了,而且我对React场景还比较陌生。

错误

Runtime Error
Error: Cannot find module 'ReactNative' from 'react-native.js'
    at Runtime._resolveNodeModule (/Users/Yulfy/Downloads/COMPANY-Mobile/node_modules/jest-cli/src/Runtime/Runtime.js:451:11)
    at Object.<anonymous> (/Users/Yulfy/Downloads/COMPANY-Mobile/node_modules/react-native/Libraries/react-native/react-native.js:181:25)
    at Object.<anonymous> (/Users/Yulfy/Downloads/COMPANY-Mobile/network/connections.js:8:18)

测试代码

jest.unmock('../network/connections');
import Authorisation from '../network/connections';
describe('connections', () => {
  it('Should store and retrieve a mocked user object', () => {
    Auth = new Authorisation();
    const TEST_STRING = "CONNECTION TEST PASS";
    var userObj = {
      test_string: TEST_STRING
    };
    Auth._localStore(userObj, (storeRes) => {
      Auth._localRetrieve((retRes) => {
        expect(retRes.test_string).toEqual(TEST_STRING);
      });
    });
  });
});

connection.js

/*
*  All returns should give the following structure:
*  {isSuccess: boolean, data: object}
*/

import React, { Component } from 'react';
import { AsyncStorage } from 'react-native';
const Firebase = require('firebase');
const FIREBASE_URL = 'https://COMPANY-test.firebaseio.com';
const STORAGE_KEY = 'USER_DATA';
class Authorisation{
  _ref = null;
  user = null;
  constructor(){
  }
  getOne(){return 1;}
  _setSystemUser(userObj, authObj, callback){
    var ref = this.connect();
    if(ref === null){
      callback({isSuccess:false, data:{message:"Could not connect to the server"}});
    }
    ref = ref.child('users').child(authObj.uid);
    ref.once("value", function(snapshot){
      if(snapshot.exists()){
        callback({isSuccess:false, data:{message:"Email is currently in use"}});
        return;
      }
      ref.set(userObj, function(error){
        if(error){
          callback({isSuccess:false, data:error});
        }else{
          callback({isSuccess:true, data:authObj});
        }
      });
    });
  }
  _localStore(userObj, callback){
    AsyncStorage.setItem(STORAGE_KEY, userObj, (error) => {
      console.log("_localStore::setItem -> ", error);
      if(error){
        callback({
          isSuccess:false,
          data:'Failed to store user object in storage.'
        });
      }else{
        callback({
          isSuccess:true,
          data: userObj
        });
      }
    });
  }
  _localRetrieve(callback){
    AsyncStorage.getItem(STORAGE_KEY, (error, res) => {
      console.log("_localStore::getItem:error -> ", error);
      console.log("_localStore::getItem:result -> ", res);
      if(error){
        callback({
          isSuccess:false,
          data:error
        });
      }else{
        callback({
          isSuccess: true,
          data: res
        });
      }
    });
  }
  connect(){
    if(this._ref === null){
      _ref = new Firebase(FIREBASE_URL);
    }
    return _ref;
  }
  getUser(){
  }
  isLoggedIn(){
  }
  registerUser(userObj, callback){
    var ref = this.connect();
    if(ref === null){
      callback({isSuccess:false, data:{message:"Could not connect to the server"}});
    }
    var that = this;
    ref.createUser({
      email: userObj.username,
      password: userObj.password
    }, function(error, userData){
      if(error){
        callback({isSuccess:false, data:error});
        return;
      }
      var parseObj = {
        email: userObj.username,
        fullName: userObj.fullName
      };
      that.loginUser(parseObj, function(res){
        if(res.isSuccess){
          that._setSystemUser(parseObj, res.data, callback);
        }else{
          callback(res);//Fail
        }
      });
    });
  }
  loginUser(userObj, callback){
    var ref = this.connect();
    if(ref === null){
      callback({isSuccess:false, data:{message:"Could not connect to the server"}});
    }
    ref.authWithPassword({
      email: userObj.email,
      password: userObj.password
    }, function(error, authData){
      if(error){
        callback({isSuccess:false, data:error.message});
      }else{
        callback({isSuccess:true, data:authData});
      }
    });
  }
}
export default Authorisation;

如果你已经读到这里了,谢谢你抽出时间!

-Yulfy

TL;DR

我在这个GitHub Repo中有一个使用最新版本React Native(v0.28.0)运行Jest的工作示例。

-

在调查了这个问题很长一段时间后,我终于找到了解决办法。

有一些React Native应用程序与Jest集成的在线示例,但不幸的是,您不能简单地将代码复制并粘贴到代码库中,然后期望它能够工作。这是因为RN版本不同。

React Native在v0.20.0之前的版本在打包程序(node_modules/react-native/packager/react-packager/.babelrc)中包含一个.babelrc文件,一些在线示例直接将其包含在其package.json中。然而,v0.20.0及以上版本已更改为不再包含此文件,这意味着您不能再尝试包含它。因此,我建议您使用自己的.babelrc文件,并定义自己的预设和插件。

我不知道你的package.json文件是什么样子的,但它对解决这个问题非常重要。

{
    "name": "ReactNativeJest",
    "version": "0.0.1",
    "jest": {
        "scriptPreprocessor": "<rootDir>/node_modules/babel-jest",
        "unmockedModulePathPatterns": [
            "node_modules"
        ],
        "verbose": true,
        "collectCoverage": true
    },
    "scripts": {
        "test": "jest"
    },
    "dependencies": {
        "react": "^15.1.0",
        "react-native": "^0.27.2"
    },
    "devDependencies": {
        "babel-core": "^6.4.5",
        "babel-jest": "^12.1.0",
        "babel-plugin-transform-regenerator": "^6.0.18",
        "babel-polyfill": "^6.0.16",
        "babel-preset-react-native": "^1.9.0",
        "babel-types": "^6.1.2",
        "chai": "^3.5.0",
        "enzyme": "^2.3.0",
        "jest-cli": "^12.1.1",
        "react-addons-test-utils": "^15.1.0",
        "react-dom": "^15.1.0"
    }
}

另一个重要的部分是嘲讽React Native。我创建了一个__mocks__/react-native.js文件,如下所示:

'use strict';
var React = require('react');
var ReactNative = React;
ReactNative.StyleSheet = {
    create: function(styles) {
        return styles;
    }
};
class View extends React.Component {}
class Text extends React.Component {}
class TouchableHighlight extends React.Component {}
// Continue to patch other components as you need them
ReactNative.View = View;
ReactNative.Text = Text;
ReactNative.TouchableHighlight = TouchableHighlight;
module.exports = ReactNative;

通过像这样对React Native函数进行猴子补丁,您可以成功避免在尝试运行测试时出现奇怪的Jest错误。

最后,确保在项目的根目录中创建一个.babelrc文件,该文件至少包含以下行:

{
    "presets": ["react-native"],
    "plugins": [
        "transform-regenerator"
    ]
}

这个文件将用于告诉babel如何正确地转换ES6代码。

完成此设置后,您应该可以使用React Native运行Jest。我相信React Native的未来版本将使这两个框架更容易集成在一起,但这项技术将完全适用于当前版本:)

编辑

不需要手动模拟__mocks__/react-native.js文件中的ReactNative元素,您可以使用ReactNative模拟库为您进行模拟(确保将库添加到package.json文件中):

// __mocks__/react-native.js
module.exports = require('react-native-mock');

我更新了我的GitHub Repo示例来演示这种方法。

您是否尝试过在测试文件内部模拟本地react?

它适用于我的测试用例:

jest.dontMock(`../my-module-that-uses React-native.AsyncStorage`);
jest.setMock(`react-native`, {
  AsyncStorage: {
    multiGet: jest.fn(),
  },
});
const ReactNative = require(`react-native`);
const {AsyncStorage, } = ReactNative;
const myModule = require(`../my-module-that-uses React-native.AsyncStorage`);
// Do some tests and assert ReactNative.AsyncStorage.multiGet calls