Errors to configure Jest in express project

Question

I'm trying to create tests for api created with express and typescript but I get some weired erros In compilation and mock configure, follow my files:

/test/unit/services/episodeService.spec.ts

/*some imports*/

describe('Episodes Service', () => {

    let episodesQueryServiceMock: jest.Mocked<typeof episodesQueryService>
    let watchTimeInstance: jest.Mocked<WatchTimeInstance>

    beforeEach(() =>{
        jest.mock('../../../src/services/queries/episodesQueryService')
        jest.mock('../../../src/models/')
        jest.mock('../../../src/models/WatchTime')
        episodesQueryServiceMock =  episodesQueryService as jest.Mocked<typeof episodesQueryService>
    })

    it('When has no watchTime then create it', async ()=> {
        const watchTime: WatchTime =  watchTimeFactory.build() 
        (episodesQueryServiceMock.findByUserIdAndEpisodeId as jest.Mock).mockReturnValue(watchTime)
        (watchTimeInstance.save as jest.Mock).mockReturnValue(watchTime)
        const actual = await episodesService.setWatchTime(watchTime)
    })

})

in this code I have a error in first line my it

This expression is not callable. Type 'WatchTime' has no call signatures.ts(2349)

this line I try to use a factory to create a random objetc to tes using factory.ts lib, follow my factory:

./test/factories/watchTime.ts

/*some imports*/
export const watchTimeFactory = Factory.makeFactory<WatchTime>(() => ({
    userId: Number(faker.random.numeric()),
    episodeId: Number(faker.random.numeric()),
    seconds: Number(faker.random.numeric()),
    createdAt: new Date(),
    updatedAt: new Date()
}))

I thought who this was a lib bug, but I got same error using two factories libs ( Factory.ts and fishery, both use amoust same config to build factories), but if I put my factory call out of it, with my mock creations the error not happen but I got another error when I run my test

TypeError: episodesQueryServiceMock.findByUserIdAndEpisodeId.mockReturnValue is not a function

follow my jest configs

./jest.config.ts

import type {Config} from '@jest/types';
// Sync object
const config: Config.InitialOptions = {
    verbose: true,
    transform: {
        '^.+\\.tsx?$': 'ts-jest',
    },
    setupFiles: ['<rootDir>/test/setup.ts'],
    testEnvironment: 'node',
    maxWorkers: 1,
    preset: 'ts-jest'
};
export default config;

./test/setup.ts

import dotenv from 'dotenv'
dotenv.config()

process.env.DATABASE = process.env.DATABASE?.replace(/_development/, '_test')

I think my errors is something about config, please help me

thank you

Answer 1

I found my errors, have two problems in my code:

1st) My factory code it's wrong, the correct code is:

import * as Factory from "factory.ts";
import { faker } from '@faker-js/faker'
import { WatchTime } from '../../src/models'

export const watchTimeFactory = Factory.makeFactory<WatchTime>({
    userId: Number(faker.random.numeric()),
    episodeId: Number(faker.random.numeric()),
    seconds: Number(faker.random.numeric()),
    createdAt: new Date(),
    updatedAt: new Date()
});

2nd) My jest.mock() is in a wrong context, for work I need put all in same context how are my imports:

import { episodesService } from "../../../src/services/episodesService"
import { episodesQueryService } from "../../../src/services/queries/episodesQueryService"
import { WatchTime } from "../../../src/models/"
import { WatchTimeInstance } from "../../../src/models/WatchTime"
import { watchTimeFactory } from "../../factories/watchTime"

// this place
jest.mock('../../../src/services/queries/episodesQueryService')
jest.mock('../../../src/models/')
jest.mock('../../../src/models/WatchTime')

describe('Episodes Service', () => {

    it('When has no watchTime then create it', async ()=> {
        const watchTime =  watchTimeFactory.build();
        (episodesQueryService.findByUserIdAndEpisodeId as jest.Mock).mockReturnValue(watchTime);
        const actual = await episodesService.setWatchTime(watchTime);
    })

})

this steps solve my problems, thank you