Issue while (unit test) mocking container.get service

[lineldcosta]

Hello all,

I have some issues in unit testing container.get(service), checkout the below code.

import * as _ from 'lodash';
import {Service, Inject, Container} from 'typedi';
import OTPService from '../otp/index';

@Service()
export default class DevicechangeService {
  constructor(@Inject('devicechangeModel')private devicechangeModel, @Inject('otpModel')private otpModel, @Inject('logger')private logger,) {}

  /**
   *
   * Service to change the device
   *
   * @method deviceChange
   * @param {number} accountId
   * @param {string} deviceId
   * @param {number} mobile
   * @return {object} resolves after sending otp
   */

  public async deviceChange(accountId : number, deviceId : string, newdeviceId : string, created : number, mobile : number,) : Promise < any > {
    try {
      await this
        .devicechangeModel
        .addDeviceChangeDetails(accountId);

       let OTPServiceInstance = Container.get(OTPService);


      await this
        .otpModel
        .updateOTPtoInactiveForModule('DEVICE_CHANGE', accountId);
      //get the new otp

        //get the user details
        //send the otp
        let result = await OTPServiceInstance.sendOTP(serviceprovider, mobile, otpMessage, isd);
        if (result instanceof Object) {
          return result;
        }
        return true;
      } else {
        return {
          field: 421,
          message: errorCode('account').getMessage(421)
        };
      }
    } catch (e) {
      throw e;
    }
  }
}

Here i am not able to set mock class for OTPService, so not able to alter container.get(OTPService) from the above code.

I have tried below but still it does'nt come inside mocked service.

@Service()
class OTPService {
  public generateOTP : any = jest
    .fn()
    .mockImplementation(async(accountId : number, deviceId : string, status : string) => new Promise((resolve : any) => {
      console.log('calls here')
      resolve({})
    }),);
  public sendOTP : any = jest
    .fn()
    .mockImplementation(async(serviceprovider : string, mobile : number, otpMessage : string, isd : number) => new Promise((resolve : any) => resolve({})),);
}

describe('Account', () => {
  beforeEach(done => {
    Container.set(OTPService, new OTPService());
    done();
  });
  describe('#deviceChange', () => {
    it('check everyting cool', async done => {
      let logger = {};
      let otpModel = {
        updateOTPtoInactiveForModule: jest
          .fn()
          .mockImplementation(async(deviceChange : string, accountId : number) => new Promise((resolve : any) => resolve(true))),
        getUserPhoneService: jest
          .fn()
          .mockResolvedValue(true)
      };
      let devicechangeModel = {
        addDeviceChangeDetails: jest
          .fn()
          .mockResolvedValue(true),
        updateDeviceChangeToInactive: jest
          .fn()
          .mockResolvedValue(true)
      };
      // Container.set('OTPService', new OTPService());
      let DeviceChangeServiceInstance = new DeviceChangeService(devicechangeModel, otpModel, logger);
      let deviceChangeStatus = DeviceChangeServiceInstance.deviceChange(accountId, deviceId, newdeviceId, created, mobile);
    });
  });
});

Guys any input how to solve this...

[rafalfigura]

This don't for me either. Can comeone help?

[lineldcosta]

I came to know that we should not use Container.get() in service layer instead use dependency injection so its easy to write the unit tests.

[rafalfigura]

I came to know that we should not use Container.get() in service layer instead use dependency injection so its easy to write the unit tests.

Can you give some example code?

[maximeshr]

I just discovered this library and I want to use it on important projects.
Here an example based on what I learned reading the README:

// bye.ts
import { Container, Service, Inject } from "typedi";

@Service("service.a")
class ServiceA {
  get() {
    return "a";
  }
}

@Service("service.b")
class ServiceB {
  update() {
    return "b";
  }
}

export class Bye {
  a: ServiceA;
  b: ServiceB;

  constructor() {
    this.a = Container.get("service.a");
    this.b = Container.get("service.b");
  }

  pwouet() {
    return this.a.get() + this.b.update();
  }
}

// bye.test.ts
import { Container } from "typedi";
import { Bye } from "./bye";

// Create fake objects to mock class (easiest method I found)
const fakeA = {
  get: jest.fn().mockReturnValue("A"),
};

const fakeB = {
  update: jest.fn().mockReturnValue("B"),
};

// Overwrite services by mocks
Container.set([
  { id: "service.a", value: fakeA },
  { id: "service.b", value: fakeB },
]);

beforeEach(() => {
  jest.clearAllMocks();
});

describe("Bye", () => {
  it("should return AB", () => {
    const bye = new Bye();

    expect(bye.pwouet()).toBe("AB"); // ab has been overwritten properly
  });

  it("should return Ax", () => {
    // Redefine fakeB for this test only
    const fakeB = {
      update: jest.fn().mockReturnValue("x"),
    };
   
    // Overwrite the service.b
    Container.set("service.b", fakeB);

    const bye = new Bye();

    expect(bye.pwouet()).toBe("Ax");
    expect(fakeB.update).toHaveBeenCalledTimes(1);
  });
});

You have more information at the bottom of this section: https://github.com/typestack/typedi#usage-with-typescript

I'm not sure it will help but it worked to me!

[NoNameProvided]

If you still experience the issue please provide a narrow (~10-15 lines) reproducible error case.

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