reactjs - Jest 类型错误 : is not a constructor in Jest. 模拟

Question

我正在尝试使用 jest 编写单元测试用例，并且需要模拟以下模式。我收到 TypeError: is not a constructor。

用例:我的用例如下所述

我的组件.js :

 import serviceRegistry from "external/serviceRegistry";


        serviceRegistry.getService("modulename", "servvice").then(
              service => {
                let myServiceInstance = new service();
                myServiceInstance.init(p,d) 
        })

我的组件.spec.js

jest.mock('external/serviceRegistry', () => {
      return {
        getService: jest.fn(() => Promise.resolve({
          service: jest.fn().mockImplementation((properties, data, contribs) => {
            return {
              init: jest.fn(),
              util: jest.fn(),
              aspect: jest.fn()

            };
          })
        }))
      };
    }, {virtual: true});

Answer 1

Promise返回者 getService正在解析为 object与 service prop 设置为您的构造函数模拟，但您的代码期望它直接解析为您的构造函数模拟。

更改您的 external/serviceRegistry对此进行模拟，它应该可以工作:

jest.mock('external/serviceRegistry', () => {
  return {
    getService: jest.fn(() => Promise.resolve(
      jest.fn().mockImplementation((properties, data, contribs) => {
        return {
          init: jest.fn(),
          util: jest.fn(),
          aspect: jest.fn()
        };
      })
    ))
  };
}, {virtual: true});