Jest 报告在 componentDidMount 中没有调用来自酶浅层组件的方法

Question

所以我有一个通用类组件：

import React, { Component } from "react";

export default class CompTest extends Component {
  someFunc() {}

  componentDidMount() {
    this.someFunc();
  }

  render() {
    return <div>Hey</div>;
  }
}

我想检查someFunc 是否至少被调用一次（在componentDidMount 内）

describe("<CompTest /> componendDidMount", () => {
  it("should call someFun()", () => {
    const wrapper = shallow(<CompTest />);
    const instance = instance();
    jest.spyOn(instance, "someFun");

    expect(instance.someFunc).toHaveBeenCalledTimes(1);
  });
});

但是我得到： Expected mock function to have been called one time, but it was called zero times.

根据酶 v3 文档：As of Enzyme v3, the shallow API does call React lifecycle methods such as componentDidMount and componentDidUpdate.

我的测试有什么问题？谢谢。

Answer 1

（这里是酶维持剂）

问题在于，在原始文件已被传递到渲染树之后，您正在监视 someFunc 方法。试试这个：

describe("<CompTest /> componendDidMount", () => {
  it("should call someFun()", () => {
    jest.spyOn(CompTest.prototype, 'someFunc');
    const wrapper = shallow(<CompTest />);

    expect(wrapper.instance().someFunc).toHaveBeenCalledTimes(1);
  });
});