我如何测试玩笑和应用功能? [英] How do I test call and apply functions in jest?

问题描述

这是我的 callnapply.js 文件

const callAndApply = {
  caller(object, method, nameArg, ageArg, tShirtSizeArg) {
    method.call(object, nameArg, ageArg, tShirtSizeArg);
  },
  applier(object, method, argumentsArr) {
    method.apply(object, argumentsArr);
  },
};
module.exports = callAndApply;

这是测试文件的片段，其中包含无效的测试:

And here's a snippet from the test file which contains the non-working test:

const callnapply = require('./callnapply');

test('testing Function.prototype.call as mock function', () => {
    const outer = jest.fn(); 
    const name = 'Aakash';
    const age = 22;
    const tee = 'M';
    callnapply.caller(this, outer, name, age, tee);
    expect(outer.call).toHaveBeenCalledWith(name, age, tee);
});

如何编写测试以检查我通过的method实际上是否仅由Function.prototype.call函数调用?我想检查是否正在调用.call()，而不是为method调用编写的其他实现.

How do I write the test to check if the method that I am passing is, in fact, being called by the Function.prototype.call function only? I want to check whether .call() is being called and not some other implementation that has been written for the method call.

推荐答案

您可以模拟.call()方法本身:

const outer = function() {}
outer.call = jest.fn()

然后，您可以在outer.call上进行常规的笑话模拟测试.

Then you can do usual jest mock tests on outer.call.

这是工作测试文件:

const callnapply = require('./callnapply');

test('testing Function.prototype.call as mock function', () => {
    const outer = function() {};
    outer.call = jest.fn();
    const name = 'Aakash';
    const age = 22;
    const tee = 'M';
    callnapply.caller(this, outer, name, age, tee);
    expect(outer.call).toHaveBeenCalledWith(this, name, age, tee);
});

请参见此有效的REPL .

这篇关于我如何测试玩笑和应用功能?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！