Mock EntityManager for unit test

Issue type: [x ] question

Database system/driver: [ x] mssql

TypeORM version: [ x] 0.1.21

Steps to reproduce or a small repository showing the problem:

Hi! Could you help me with testing my nest controller, please? I use manager: EntityManager in controller’s method and I don’t understand how I should mock it. In this test I don’t need to test manager or service’s function, which uses this manager. I just want to check if this function is called.

CONTROLLER

@Put('/file')
@UseInterceptors(FileInterceptor('file'))
@Transaction()
 uploadFile(@Body() body,
                   @UploadedFile() file,
                   @TransactionManager() manager: EntityManager) {
    return this.ordersService.uploadFile(manager, file, body);
}

TEST

it('uploadFile method should return success', () => {
    const body = {...};      /* some data */
    const file = {};            /* empty object */
    const manager = {};   /* empty object */
    const mock = spyOn(ordersService, 'uploadFile').and.returnValue(Promise.resolve({}));

    ordersController.uploadFile(body, file, manager).then(response => {
        expect(mock).toHaveBeenCalledWith(manager, file, body);
        expect(response).toEqual({});
    });
});

But when I run this test I receive an error:

ConnectionNotFoundError: Connection "default" was not found.

Because decorator @TransactionManager try to create EntityManager. Could you advise me how to mock EntityManager for unit test or maybe you have ready-made solution, which I couldn’t find in the documentation. Thank you!

[jeremymcjunkin]

@ali-habibzadeh Did you ever figure this out? I’ve run into the same issue. I am having a hell of a time trying to figure out how to mock the typeorm connection class.

[ali-habibzadeh]

You could stub out getConnection:

import * as typeorm from 'typeorm'
import {stub, createStubInstance, createSandbox} from 'sinon'

const sandbox = createSandbox()
const connection = createStubInstance(typeorm.Connection)
let manager
connection.transaction.callsFake(async fn => fn(manager))
stub(typeorm, 'getConnection').returns(connection)

beforeEach(() => {
  manager = sandbox.createStubInstance(typeorm.EntityManager)
})

afterEach(() => sandbox.restore())

Something like that

Argument of type ‘SinonStubbedInstance<Connection>’ is not assignable to parameter of type ‘Connection’. Type ‘SinonStubbedInstance<Connection>’ is missing the following properties from type ‘Connection’: findMetadata, buildMetadatas

Any ideas?