test(@nestjs/typeorm): add test for connectionFactory

Add unit test for async options with connectionFactory.

tests/e2e/typeorm-async-connection-factory-options.spec.ts

@@ -0,0 +1,30 @@
+import { INestApplication } from '@nestjs/common';
+import { Test } from '@nestjs/testing';
+import * as request from 'supertest';
+import { AsyncConnectionFactoryOptionsFactoryModule } from '../src/async-connection-factory-options.module';
+import { Server } from 'http';
+
+describe('TypeOrm (async configuration with connectionFactory)', () => {
+  let server: Server;
+  let app: INestApplication;
+
+  beforeEach(async () => {
+    const module = await Test.createTestingModule({
+      imports: [AsyncConnectionFactoryOptionsFactoryModule],
+    }).compile();
+
+    app = module.createNestApplication();
+    server = app.getHttpServer();
+    await app.init();
+  });
+
+  it(`should return created entity`, () => {
+    return request(server)
+      .post('/photo')
+      .expect(201, { name: 'Nest', description: 'Is great!', views: 6000 });
+  });
+
+  afterEach(async () => {
+    await app.close();
+  });
+});

tests/src/async-connection-factory-options.module.ts

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+import { Module } from '@nestjs/common';
+import { createConnection } from 'typeorm';
+import { TypeOrmModule } from '../../lib';
+import { Photo } from './photo/photo.entity';
+import { PhotoModule } from './photo/photo.module';
+
+@Module({
+  imports: [
+    TypeOrmModule.forRootAsync({
+      useFactory: () => ({
+        type: 'postgres',
+        host: '0.0.0.0',
+        port: 3306,
+        username: 'root',
+        password: 'root',
+        database: 'test',
+        entities: [Photo],
+        synchronize: true,
+        retryAttempts: 2,
+        retryDelay: 1000,
+      }),
+      connectionFactory: async (options) => {
+        // Realistically, this function would be used for more than simply creating a connection,
+        // i.e. checking for an existing and active connection prior to creating a new one.
+        // However, including that logic here causes runtime test errors about variables being used before assignment.
+        // Therefore, given the simple nature of this test case, simply create and return a connection.
+        const connection = await createConnection(options!);
+        return connection;
+      },
+    }),
+    TypeOrmModule.forRoot({
+      name: 'connection_2',
+      type: 'postgres',
+      host: '0.0.0.0',
+      port: 3306,
+      username: 'root',
+      password: 'root',
+      database: 'test',
+      entities: [Photo],
+      synchronize: true,
+      retryAttempts: 2,
+      retryDelay: 1000,
+    }),
+    PhotoModule,
+  ],
+})
+export class AsyncConnectionFactoryOptionsFactoryModule {}