Best pratice for MongoDB with mongoose

[artecoop]

I'm building a new application with graphql-modules, this time with tests in mind (shame on me for not doing it before).

I'm using the fastify ecosystem and mongoose to connect to my MongoDB database.
Defining the entry point of the app, I instantiate mongoose like this:

import Mongoose from 'mongoose';

...

Mongoose.connect(mongodbUrl, { useNewUrlParser: true, useUnifiedTopology: true, useCreateIndex: true }).catch(err => console.log(err));

...

const print = await server.listen(port, address);
console.log(`Listening on ${print}`);

After defining a schema, I can create a provider for my module for example:

import { Injectable, Scope } from 'graphql-modules';

import { MyModel } from '../models/my-model';

@Injectable({ scope: Scope.Operation })
export class MyProvider {
    public async getAll(): Promise<Foo[]> {
        return await MyModel.find({}).sort({ order: 1 });
    }
}

Now, this is spotless when running the app, but I cant test it because the connection timeout.
Using testkit I can instantiate modules but obviously not the entire app, so executing query in tests always fail.

I think I need to have the database at module level, not instantiated at server level to run test. I don't know how tho: What's the best way to have mongodb available across various modules without instantiating it from the server?