Nestjs database testing code example

Example 1: nestjs test db

/* src/utils/testing-helpers/createMemDB.js */
import { createConnection, EntitySchema } from 'typeorm'
type Entity = Function | string | EntitySchema<any>

export async function createMemDB(entities: Entity[]) {
  return createConnection({
    // name, // let TypeORM manage the connections
    type: 'sqlite',
    database: ':memory:',
    entities,
    dropSchema: true,
    synchronize: true,
    logging: false
  })
}

Example 2: nestjs test db

// books.service.test.ts
import { Test, TestingModule } from '@nestjs/testing';
import { HttpModule, HttpService } from '@nestjs/common';
import { TypeOrmModule, getRepositoryToken } from '@nestjs/typeorm';
import { Repository } from 'typeorm';

import { BooksService } from './books.service';
import { Book } from './book.entity';
import { createTestConfiguration } from '../../test/db';

describe('BooksService', () => {
  let module: TestingModule;
  let service: BooksService;
  let httpService: HttpService;
  let repository: Repository<Book>;

  beforeAll(async () => {
    module = await Test.createTestingModule({
      imports: [
        HttpModule,
        TypeOrmModule.forRoot(createTestConfiguration([Book])),
        TypeOrmModule.forFeature([Book]),
      ],
      providers: [BooksService],
    }).compile();

    httpService = module.get<HttpService>(HttpService);
    service = module.get<BooksService>(BooksService);
    repository = module.get<Repository<Book>>(getRepositoryToken(Book));
  });

  afterAll(() => {
    module.close();
  });

  it('should be defined', () => {
    expect(service).toBeDefined();
  });