Mock Prisma client

[thermsdorff]

Hello !

I need to mock prisma client to avoid database connection during tests.
Prisma recommend to mock client directly : https://www.prisma.io/docs/guides/testing/unit-testing

But since the instantiation of the Prisma client is handled by @tsed/prisma what is the best way to mock Prisma client while using tsed ?

[Romakita]

Hello @thermsdorff,

You can try that:

import { PrismaClient } from '@prisma/client'
import { mockDeep, mockReset, DeepMockProxy } from 'jest-mock-extended'

export function mockPrismaService() {
   registerProvider({
      provide: PrismaService,
      useClass: null,
      useFactory: () => {
        return mockDeep<PrismaClient>()
      },
      hooks: {
        $onDestroy(instance: any) {
           mockReset(instance);
        }
      }
   })
}
export function restorePrismaService() {
     registerProvider({provide: PrismaService, useClass: PrismaService})
}

[thermsdorff]

Hello @Romakita !

Thank you for quick answer.

I tried to inject mock through PlatformTest invoke method, but it seems PrismaService onInit method is trigger before at platformTest init through injectorService.

Can you share me a way to override injectorService during tests ?

PS: I have successfully mock prisma repositories but still get stuck with prismaService initialisation

[Romakita]

Hello,
I already shared you a way to override injector.
You have to mockPrismaService before PlateformTest.bootstrap()

[thermsdorff]

Works like a charm !

I was using the mock after the bootstrap 🤦

Thanks for your time

[Romakita]

Perfect ;)

[Romakita]

Hello @thermsdorff

I decided to implement an official way to mock service directly on PlatformTest.create, PlatformTest.bootstrap!

The testing page on the website will describe official the process to mock service correctly ;).

Thanks for your discussion because this feature was missing!

See you
Romain