Issue:
When using TestingModule.get() in NestJS, why do objects retrieved from getEntityManagerToken() and getRepositoryToken() refer to different entities?
Explanation:
The object obtained with getEntityManagerToken() represents an unmocked EntityManager instance. Conversely, the object obtained with getRepositoryToken() corresponds to a mocked Repository during moduleRef creation.
Sample Code:
import { Test, TestingModule } from '@nestjs/testing';
import { getEntityManagerToken, getRepositoryToken } from '@nestjs/typeorm';
import { EntityManager } from 'typeorm';
const mockEntityManager = () => ({
query: jest.fn(),
find: jest.fn(),
findOne: jest.fn(),
});
describe('TEST', () => {
let sut: Service;
let replicaRepositoryStub: any;
let replicateManagerStub: any;
beforeEach(async () => {
const moduleRef: TestingModule = await Test.createTestingModule({
providers: [
Service,
{
provide: getEntityManagerToken('replica'),
useValue: mockEntityManager(),
},
{
provide: getRepositoryToken(Entity, 'replica'),
useValue: mockEntityManager(),
},
],
}).compile();
sut = moduleRef.get<Service>(Service);
replicaRepositoryStub = moduleRef.get(getRepositoryToken(Entity, 'replica'));
replicateManagerStub = moduleRef.get(getEntityManagerToken('replica'));
});
it('test1', async () => {
replicaRepositoryStub.findOne.mockResolvedValue('test'); // works fine
replicateManagerStub.findOne.mockResolvedValue('test'); // This line triggers an error.
});
});
Error Message:
replicateManagerStub.findOne.mockResolvedValue is not a function
TypeError: replicateManagerStub.findOne.mockResolvedValue is not a function
at Object.<anonymous> (PATH)
Queries:
- What causes this disparity between EntityManager and Repository instances?
- Is there a way to acquire EntityManager via moduleRef in NestJS?
- If so, how can it be achieved?
I have experimented with various methods to address this issue and confirmed that the object provided by moduleRef results in a fresh EntityManager instance.