Jest报告说，来自酶浅层组件的方法尚未在componentDidMount中调用

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

（酶保持者在这里）

问题是，在原始方法已传递到渲染树中后，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);
  });
});