Starts and Stops mongo-memory-db

mongodb-testing.module.ts

import { ConfigService } from '@leocloud/shared';
import { DynamicModule, Inject, Module, OnApplicationBootstrap, OnApplicationShutdown } from '@nestjs/common';
import { MongoMemoryServer } from 'mongodb-memory-server';
import { connect, disconnect } from 'mongoose';
import { Subject } from 'rxjs';

const MONGO_DB_TESTING_COLLECTION_NAMES = 'MongoDbTestingCollectionNames';

const mongoDbIsBootstrapped = new Subject<void>();

@Module({})
export class MongoDbTestingModule implements OnApplicationBootstrap, OnApplicationShutdown {
    private server: MongoMemoryServer;
    private mongoose: typeof import('mongoose');

    static bootstrap(collectionNames: string[]): DynamicModule {
        return {
            module: MongoDbTestingModule,
            providers: [
                {
                    provide: MONGO_DB_TESTING_COLLECTION_NAMES,
                    useValue: collectionNames,
                },
            ],
        };
    }

    constructor(@Inject(MONGO_DB_TESTING_COLLECTION_NAMES) private collectionNames: string[], private configService: ConfigService) {}

    async onApplicationBootstrap() {
        await this.createServer();
        await this.createCollections();

        mongoDbIsBootstrapped.next();
    }

    async onApplicationShutdown(signal?: string) {
        await disconnect();
        await this.server.stop();
    }

    private async createServer() {
        this.server = await MongoMemoryServer.create();

        const uri = this.server.getUri();

        // Make uri available so that DatabaseModule can connect to MongoDB
        process.env.MONGODB_URI = uri;

        this.mongoose = await connect(uri, { dbName: this.configService.get('MONGODB_DBNAME') });
    }

    private async createCollections() {
        this.collectionNames.forEach(async collectionName => await this.mongoose.connection.createCollection(collectionName));
    }
}