Dependency Injection Test Class with Vite

[joseluisgs]

Hi friends
I would like to test a class that uses another class as dependence in its constructor.
My idea es mock this class and methods, pass the mock toe the class that I am testing and simulate the works similar that I do with mockito or jest, like this: https://stackoverflow.com/questions/55522669/jest-mocking-of-classes-with-di-dependencies

I will try, but I'm not getting it, maybe because I'm still not very expert in Vitest with Mocks.

I have check the doc:
https://vitest.dev/guide/mocking.html#globals
https://vitest.dev/api/#vi-mocked

I use TypeScript

Here it 's my code: https://github.com/joseluisgs/Prueba-Tecnica-Cola-Prioridad-Sin-Repetidos-Kotlin/blob/main/typescript/tests/controllers/ProcesosController.test.ts

Could you help me or give me any advice?

Thank you so much!

[sheremet-va]

https://vitest.dev/guide/mocking.html#cheat-sheet

[joseluisgs]

Thank you very much

I check it, but I can't do it, could you check this code and help me, or give me a siimple example
https://github.com/joseluisgs/Prueba-Tecnica-Cola-Prioridad-Sin-Repetidos-Kotlin/blob/main/typescript/tests/controllers/ProcesosController.test.ts
Thank you

[joseluisgs]

Ok, I have this
ColaPrioritaria is a simple TDA a queue (repository)
In my Controller, I use is a detedence.

Here is a test without a mock

describe('Suite de test de Controlador de Procesos', () => {
  let colaPrioritaria: ColaPrioritariaImp
  let procesosController: ProcesosController

  // En cada test creamos la cola
  beforeEach(() => {
    colaPrioritaria = new ColaPrioritariaImp()
    procesosController = new ProcesosController(colaPrioritaria)
  })

  test('debería obtener todos los procesos respetando prioridad', () => {
    const proceso1 = new Proceso(1, 'Proceso 1', 1)
    const proceso2 = new Proceso(2, 'Proceso 2', 2)
    colaPrioritaria.push(proceso1)
    colaPrioritaria.push(proceso2)

    const res = procesosController.getAll()

    expect(res).toEqual([proceso2, proceso1])
    assert.equal(res.length, 2)
    assert.equal(res[0], proceso2)
    assert.equal(res[1], proceso1)
    assert.isTrue(res[0].prioridad >= res[1].prioridad)
  })
})

I try to make a mock of ColaPrioritaria

I use TypeScript

import { describe, test, assert, beforeEach, afterEach, expect, vi } from 'vitest'
import Proceso from '../../src/models/Proceso'
import ProcesosController from '../../src/controllers/ProcesosController'
import ColaPrioritariaImp from '../../src/repositories/ColaPrioritariaImp'
// import ProcesosException from '../../src/errors/ProcesosException'


vi.mock('../../src/repositories/ColaPrioritariaImp', () => {
  const ColaPrioritariaImp = vi.fn(() => ({
    getAll: vi.fn(() => [new Proceso('1', 'proceso 1', 1), new Proceso('2', 'proceso 2', 2)]),
  }))
  return { ColaPrioritariaImp }
})

describe('DI Test', () => {
  let cola: ColaPrioritariaImp

  beforeEach(() => {
    cola = new ColaPrioritariaImp()
  })

  afterEach(() => {
    vi.clearAllMocks()
  })

test('Foo', async () => {
    const controller: ProcesosController = new ProcesosController(cola)

    const result = await controller.getAll()

    expect(cola.getAll).toBeCalledTimes(1)
    expect(result.length).toBe(2)
  })

I have this error:

 FAIL  tests/controllers/ProcesosController.test.ts > DI Test > Foo
TypeError: Cannot read properties of undefined (reading 'getAll')
 ❯ ProcesosController.getAll src/controllers/ProcesosController.ts:37:21
     35| 
     36|   public getAll(): Proceso[] {
     37|     return this.cola.getAll()
       |                     ^
     38|   }
     39| }
 ❯ tests/controllers/ProcesosController.test.ts:29:36

I try to use vi.mocked

[joseluisgs]

I try this and works

But I am not very sure if it is a correct option, because I have tried others from the doc as I have put in previous messages and perhaps I am doing it wrong.

I appreciate any help to improve myself.

// Creamos nuestro objeto de mock completo de Cola Prioritaria
const ColaPrioritariaImp = vi.fn(() => ({
  getAll: vi.fn(() => [new Proceso(2, 'proceso 2', 2), new Proceso(1, 'proceso 1', 1)]),
  size: vi.fn(() => 2),
  push: vi.fn(),
  pop: vi.fn(() => new Proceso(1, 'proceso 1', 1)),
  isEmpty: vi.fn(() => false),
  getById: vi.fn(() => new Proceso(1, 'proceso 1', 1)),
}))
describe('Suite de test de Controlador de Procesos Mock Repositorio Cola Prioritaria', () => {
  let colaPrioritaria: ColaPrioritaria
  let procesosController: ProcesosController

  beforeEach(() => {
    colaPrioritaria = new ColaPrioritariaImp()
    procesosController = new ProcesosController(colaPrioritaria)
  })

  afterEach(() => {
    vi.clearAllMocks()
  })

  test('debería obtener todos los procesos respetando prioridad', () => {
    const res = procesosController.getAll()

    expect(colaPrioritaria.getAll).toBeCalledTimes(1)
    expect(res.length).toBe(2)
    assert.equal(res.length, 2)
    assert.isTrue(res[0].prioridad >= res[1].prioridad)
  })
})