pg-mem with typeorm for in memory jest testing

Question

i have a express app i am creating in typescript. I also am using typeorm as my orm for connecting to the database and actioning on it.

I already have jest unit tests but i also wanted to create integration tests with my database. I was using postgreSQL but i dont want to actually connect to my actual db every time i run the database. With this in mind i wanted to use a in memory db just for testing purposes.

typeorm and sqlite work very well for in memory db support but i found pg-mem for postgresql but cant find out how to really integrate it and any help would be useful.

i had my data-source file created as:

import { DataSource } from 'typeorm';
import { MysqlConnectionOptions } from 'typeorm/driver/mysql/MysqlConnectionOptions';
import logger from '@common/utils/logger';

export const AppDataSource = new DataSource({
  type: process.env.DB_TYPE as MysqlConnectionOptions['type'],
  host: process.env.DB_HOST,
  port: parseInt(process.env.DB_PORT || '5432', 10),
  username: process.env.DB_USERNAME,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
  synchronize: true,
  logging: true,
  logger: 'file',
  entities: [__dirname + '/**/*.entity{.ts,.js}'],
  migrationsTableName: 'migrations',
  migrations: ['migrations/*{.ts,.js}']
});

export const initializeDataSource = async (): Promise<void> => {
  const fN = 'initializeDataSource';
  try {
    await AppDataSource.initialize();
    logger.info(`${fN} - Data Source has been initialized!`);
  } catch (err) {
    logger.error(`${fN} - Error during Data Source initialization:`, err);
    throw err;
  }
};

and then in my app file i start the server and db by:

AppDataSource.initialize()
  .then(async () => {
    const PORT = process.env.PORT || '3001';
    app.listen(PORT, () => {
      logger.info(`Server is running on port ${PORT}`);
    });
  })
  .catch(error => logger.error('Database connection error: ', error));

but now how i can utilize jest to mock that to use pg-mem i cant figure it out. any help would be greatly appreciated.

Any other suggestions i am open to as well