how to unit test nest with fastify

Question

I searched the documentation for Next, but I didn't find much on how to unit test main.ts

async function bootstrap() {
  const app = await NestFactory.create<NestFastifyApplication>(
    AppModule,
    new FastifyAdapter(),
  );
  
  app.useGlobalPipes(new ValidationPipe());
  const config = new DocumentBuilder()
    .setTitle('Api')
    .addTag('Api', 'User API')
    .build();

  const document = SwaggerModule.createDocument(app, config);

  SwaggerModule.setup('user', app, document);

  await app.listen(process.env.CONTAINER_PORT, '0.0.0.0');

  console.log(`port: ${process.env.EXTERNAL_PORT}`);

}

bootstrap();