InversifyJS联合测试符号存根

Question

我正试图在我的InversifyJS项目上编写单元测试代码。路由测试(使用supertest)工作正常。然后尝试编写sinon stub，spy测试，但不可能成功。下面给出我的示例代码：

DemoRoute

@injectable()
class DemoRoute implements IDemoRoute {
 private _demoController:IDemoController;

 constructor( @inject(TYPES.IDemoController) demoController:IDemoController ) {
   this._demoController = demoController;
 }

 create(req: Request, res: Response, next: NextFunction) {
   return this._demoController.create(req.body)
 }
}

Demo.test.ts

import "reflect-metadata";
import * as sinon from "sinon";
const sandbox = sinon.createSandbox();

describe.only("Demo Spec 2", () => {
   demoController = container.get<IDemoController>(TYPES.IDemoController);

   beforeEach((done) => {
      insertStub = sandbox.stub(demoController, 'create');
      done();
   });

   afterEach(() => {
     sandbox.restore();
   });

   it("Should call demo route url", async done => {
     demoRoute  = container.get<IDemoRoute>(TYPES.IDemoRoute);
     const stub =  insertStub.returns(Promise.resolve({ body: { name: "test xyz", code: "test abc"} }));
     const result = await demoRoute.create({body: demoData.validData}, {send: (params) => params});
     expect(stub).to.have.been.called; // throw error
     done();
   });
}

单元测试中的错误

UnhandledPromiseRejectionWarning: AssertionError:期望create至少被调用一次，但从未被调用过

我该如何解决这个问题？提前谢谢。

Answer 1

原因是注入到DemoRoute的DemoRoute实例和通过以下语句获得的demoController实例：

const demoController = container.get<IDemoController>(TYPES.IDemoController);

它们是两个不同的demoController实例。您刚刚在测试文件中为demoController实例创建了一个存根。

在了解了这一点之后，我们可以为DemoController.prototype.create创建一个存根，它将应用于所有实例。

例如。

demoRoute.ts

import "reflect-metadata";
import { IDemoRoute, IDemoController } from "./interfaces";
import { NextFunction } from "express";
import { TYPES } from "./types";
import { inject, injectable } from "inversify";

@injectable()
export class DemoRoute implements IDemoRoute {
  private _demoController: IDemoController;

  constructor(@inject(TYPES.IDemoController) demoController: IDemoController) {
    this._demoController = demoController;
  }

  create(req: Request, res: Response, next: NextFunction) {
    return this._demoController.create(req.body);
  }
}

demo.test.ts

import "reflect-metadata";
import sinon from "sinon";
import { TYPES } from "./types";
import { IDemoController, IDemoRoute } from "./interfaces";
import { container } from "./inversify.config";
import { DemoController } from "./demoController";
import { expect } from "chai";

const sandbox = sinon.createSandbox();

describe.only("Demo Spec 2", () => {
  const demoController = container.get<IDemoController>(TYPES.IDemoController);
  let insertStub: sinon.SinonStub<any, any>;
  beforeEach(() => {
    insertStub = sandbox.stub(DemoController.prototype, "create");
  });

  afterEach(() => {
    sandbox.restore();
  });

  it("Should call demo route url", async () => {
    const demoData = { validData: {} };
    const demoRoute = container.get<IDemoRoute>(TYPES.IDemoRoute);
    // different demoController instances
    expect(demoRoute["_demoController"]).not.to.be.equal(demoController);
    insertStub.returns(Promise.resolve({ body: { name: "test xyz", code: "test abc" } }));
    const nextStub = sinon.stub();
    const result = await demoRoute.create(
      { body: demoData.validData } as any,
      { send: (params) => params } as any,
      nextStub,
    );
    sinon.assert.calledOnce(insertStub);
  });
});

包含覆盖率报告的单元测试结果：

 Demo Spec 2
    ✓ Should call demo route url


  1 passing (25ms)

---------------------|----------|----------|----------|----------|-------------------|
File                 |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
---------------------|----------|----------|----------|----------|-------------------|
All files            |    96.08 |      100 |       80 |    95.56 |                   |
 demo.test.ts        |    95.83 |      100 |       80 |    95.45 |                31 |
 demoController.ts   |    85.71 |      100 |       50 |       80 |                 7 |
 demoRoute.ts        |      100 |      100 |      100 |      100 |                   |
 inversify.config.ts |      100 |      100 |      100 |      100 |                   |
 types.ts            |      100 |      100 |      100 |      100 |                   |
---------------------|----------|----------|----------|----------|-------------------|

完整的示例源代码：https://github.com/mrdulin/mocha-chai-sinon-codelab/tree/master/src/stackoverflow/59103140

Answer 2

我们能够通过从反版本容器中提取实例的方法，再加上使用sinon.createStubInstance()来模拟构造函数来实现顽固性。看起来是这样的：

describe.only("Demo Spec 2", () => {
   demoController = container.get<IDemoController>(TYPES.IDemoController);
   demoControllerStub = sinon.createStubInstance(IDemoController) as SinonStubbedInstance<IDemoController>;
   beforeEach((done) => {
      insertStub = sinon.stub(demoController, 'create');
      done();
   });

   afterEach(() => {
     sandbox.restore();
   });

   it("Should call demo route url", async done => {
     demoRoute  = container.get<IDemoRoute>(TYPES.IDemoRoute);
     const stub =  insertStub.returns(Promise.resolve({ body: { name: "test xyz", code: "test abc"} }));
     const result = await demoRoute.create({body: demoData.validData}, {send: (params) => params});
     expect(demoControllerStub.create.calledOnce);
     done();
   });
}

为我们工作的另一种方式，我更喜欢，是存根实例，并取消绑定和绑定的存根实例到容器。看起来是这样的：

describe.only("Demo Spec 2", () => {
   demoControllerStub = sinon.createStubInstance(IDemoController);

   container.unbind(IDemoController);
   container.bind(IDemoController).toConstantValue(demoControllerStub);

   beforeEach((done) => {
      demoControllerStub.create.reset();
      done();
   });

   it("Should call demo route url", async done => {
     demoRoute  = container.get<IDemoRoute>(TYPES.IDemoRoute);
     const stub =  insertStub.returns(Promise.resolve({ body: { name: "test xyz", code: "test abc"} }));
     const result = await demoRoute.create({body: demoData.validData}, {send: (params) => params});
     sinon.assert.calledWith(demoControllerStub.create, sinon.match({body: demoData.validData});
     done();
   });
}