如何使用sinon，mocha chai模拟以下代码的响应

Question

任何人都可以在下面的一个示例测试方案中帮助我写信。

[storage是库（google Cloud），最后在代码行下面将返回包含文件名和日期的数组。

    function abc(){
       const files = [];
         files = await storage.bucket(bucketName).getFiles();
         return files;
    }

Answer 1

这里是单元测试解决方案：

index.ts：

import { Storage } from "@google-cloud/storage";
const storage = new Storage();

export async function abc() {
  const bucketName = "xxx-dev";
  const files = await storage.bucket(bucketName).getFiles();
  return files;
}

index.spec.ts：

import { abc } from "./";
import { Storage } from "@google-cloud/storage";
import sinon from "sinon";
import { expect } from "chai";

describe("abc", () => {
  afterEach(() => {
    sinon.restore();
  });
  it("should pass", async () => {
    const getFilesStub = sinon.stub().resolves(["file1", "file2"]);
    const bucketStub = sinon.stub(Storage.prototype, "bucket").callsFake(() => {
      return { getFiles: getFilesStub } as any;
    });
    const actual = await abc();
    expect(actual).to.be.deep.eq(["file1", "file2"]);
    sinon.assert.calledWith(bucketStub, "xxx-dev");
    sinon.assert.calledOnce(getFilesStub);
  });
});

单元测试结果覆盖率100％：

 abc
    ✓ should pass


  1 passing (39ms)

---------------|----------|----------|----------|----------|-------------------|
File           |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
---------------|----------|----------|----------|----------|-------------------|
All files      |      100 |      100 |      100 |      100 |                   |
 index.spec.ts |      100 |      100 |      100 |      100 |                   |
 index.ts      |      100 |      100 |      100 |      100 |                   |
---------------|----------|----------|----------|----------|-------------------|

软件包版本：

"@google-cloud/storage": "^4.1.3",
"sinon": "^7.5.0",
"mocha": "^6.2.2",
"chai": "^4.2.0",

源代码：https://github.com/mrdulin/mocha-chai-sinon-codelab/tree/master/src/stackoverflow/59373281