How to override an imported module in nestjs testing?

Question

I'm quite new on nestjs, met an issue regarding how to override the load function of ConfigModule, hope someone can help me out, thanks in advance!

My e2e testing:

const moduleForTesting = await Test.createTestingModule({imports: [AppModule]});

My App Module:

import config from './config/index'

@Module({
  imports: [ConfigModule.forRoot({isGlobal: true, load: [config]})]
})

My config/index file:

export default async () => {
  someConfigs: ...
}

Now I want the e2e testings use another configurations, but I don't know how to override the AppModule, nor the load function:

// AppModule
import config from './config/index' // This is ok for production, but need to be overridden in testing

...
  imports: [ConfigModule.forRoot({isGlobal: true, load: [config]})]

Does this answer your question: https://stackoverflow.com/questions/52095261/overriding-providers-in-nestjs-jest-tests? — milo526, Apr 21 '21 at 12:50
Thank you @milo526, but I still don't know how to do it. Because the link you provided seems to use `overrideProvider`, but I need to `overrideModule`, which method is not exist. — Jeff Tian, Apr 22 '21 at 01:51

score 2 · Answer 1 · answered Dec 12 '21 at 22:38

2

See withModule method in TestModuleBuilder from @jbiskur/nestjs-test-utilities

NestJS feature request: https://github.com/nestjs/nest/issues/4905

answered Dec 12 '21 at 22:38

Joe Bowbeer

3,574
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1

Looks like this is [scheduled](https://github.com/nestjs/nest/pull/8777) for 10.0.0. great work. Will look into it more but do you know off hand what the difference is when using overrideProvider vs specifying a provider in the array when created the testing module ? – Norbert Apr 17 '23 at 17:59
Quick search seems like I found it [here](https://stackoverflow.com/questions/69000993/nestjs-overrideprovider-vs-provider-in-unit-testing) – Norbert Apr 17 '23 at 18:01

score 1 · Accepted Answer · answered Apr 22 '21 at 04:15

I don't know what is the elegant NestJs way to do that, but after a deep breath, I reconsidered what I really want to do and then found a hackie way to achieve that.

I need to mock the config file so that during testing, the load array will be mocked, where the jest.mock comes to the rescue:

// e2e testing file

jest.mock('../src/config/index', () => ({
    default: async () => ({
        someConfigs: 'mocked config'
    })
})) // <--- By putting the `jest.mock` before the `createTestingModule`, the `load` array will be mocked.

...
const moduleForTesting = await Test.createTestingModule({imports: [AppModule]});

score 0 · Answer 3 · answered Sep 15 '22 at 20:00

0

You can use overridProvider

const moduleForTesting = await Test.createTestingModule({imports: [AppModule]}).overrideProvider(MyService).useValue(myServiceMock).compile()

answered Sep 15 '22 at 20:00

cgat

3,689
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How to override an imported module in nestjs testing?

3 Answers3