How to use a test base (not the main one) in NetsJS with TypeORM in unit tests?

Question

Unit testing

Greetings.
Before running the tests, I start the connection to the test database:

beforeEach(() => {
    return createConnection({
        type: "sqlite",
        database: 'testBase",
        entities: [User, SmsCodes],
        ...........
});
afterEach(() => {
    let conn = getConnection();
    return conn.close();
});

Next, I have a function that works with a real base and I need to test it:

it('Возврат: true при правильном коде SMS', async () => {
            const usersService = UsersService;
            await getRepository(SmsCodes).insert({
                email: '[email protected]',
                code: 1234,
            });
            const checkCorrectSms = await usersService.checkCorrectSmsCode('[email protected]', 1234); 
// Та самая тестируемая функция
            expect(checkCorrectSms).toBe(true);
        })

The function under test must refer to the test base, not the real one. How to do it?

Answer 1

I figured it out, here's the solution for anyone who needs it:
You need to pass the test repository to the service constructor, where this function is declared.

describe('Users Service Test /services/users.service.ts', () => {
    let usersService: UsersService;
    let smsCodesRepository: Repository<SmsCodes>;
    let testingModule: TestingModule;

    const testConnectionName = 'testConnection';

    beforeEach(async () => {
        testingModule = await Test.createTestingModule({
            providers: [
                UsersService,
                {
                    provide: getRepositoryToken(SmsCodes),
                    useClass: Repository,
                },
            ],
        }).compile();

        let connection = await createConnection({
            type: "postgres",
            database: "baseTest",
            dropSchema: true,
            entities: [SmsCodes],
            synchronize: true,
            name: testConnectionName
        });

        smsCodesRepository = getRepository(SmsCodes, testConnectionName);
        usersService = new UsersService(userRepository, smsCodesRepository);

        return connection;
    });

    afterEach(async () => {
        await getConnection(testConnectionName).close()
    });

    describe('checkCorrectSmsCode', () => {
        it('Возврат: true при правильном коде SMS', async () => {
            const mockEmail = '[email protected]'
            const mockCode = 1234;
            await smsCodesRepository.insert({
                email: mockEmail,
                code: mockCode,
            });
            const checkCorrectSms = await usersService.checkCorrectSmsCode(mockEmail, mockCode);
            expect(checkCorrectSms).toBe(true);
        })
    })
});