如何在每个测试中以不同的方式模拟导入依赖关系 [英] How to mock an imports dependency differently in each test

问题描述

我有一个导入另一个文件.我想在每个测试中以不同的方式模拟其他导入，但要通过导入它的文件来显示它.

I have a file that imports another. I want to mock the other import differently in each test yet have it show through the file that imports it.

我通过谷歌搜索尝试了各种模拟和导入方法，但没有一个奏效.

I have tried various mocking and importing approaches through googling but none have worked.

考虑文件:

settings.js

export default { mySetting: null };

store.js

import settings from "./settings";
export default {
  settings,
};

settingsDemo.js

import store from "./store";

it("default settings", () => {
  expect(store.settings.mySetting).toBe(null);
});

it("mocked to true", () => {
  expect(store.settings.mySetting).toBe(true);
});

it("mocked to false", () => {
  expect(store.settings.mySetting).toBe(false);
});

我如何在settingsDemo.js中模拟settings.js以使所有3个测试都通过?

how do I mock settings.js within settingsDemo.js to have all 3 tests pass?

推荐答案

来自 :

在ES6中，导入是有关导出值的实时只读视图."

"In ES6, imports are live read-only views on exported values."

请注意，虽然您无法更改导入的值，但是可以更改它们所引用的对象."

"Note that while you can’t change the values of imports, you can change the objects that they are referring to."

换句话说，不可能将settings分配给其他对象，但是可以更改settings的属性，并且无论导入到哪里，这些更改都会自动看到.

In other words, it is not possible to assign settings to a different object, but it is possible to change properties on settings and those changes will automatically be seen wherever it is imported.

考虑到这一点，这是一个有效的测试:

With that in mind, here is a working test:

import store from "./store";
import settings from './settings';  // import settings

it("default settings", () => {
  expect(store.settings.mySetting).toBe(null);  // SUCCESS
});

it("mocked to true", () => {
  settings.mySetting = true;  // change the mySetting property
  expect(store.settings.mySetting).toBe(true);  // SUCCESS
});

it("mocked to false", () => {
  settings.mySetting = false;  // change the mySetting property
  expect(store.settings.mySetting).toBe(false);  // SUCCESS
});

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