Cannot stub shared object from custom plugin for unit tests - hapi.js

Question

I am using a custom plugin to share a few persistence methods between some hapi modules:
const Mongoose = require('mongoose');
const Promise = require('bluebird');
const Models = require('./persistence/mongodb/models');
exports.register = (server, options, next) => {
Mongoose.Promise = Promise;
Mongoose.set('debug', 'true');
const mongoConnectionUri = process.env.MONGO_URI ||
'mongodb://localhost/foo';
Mongoose.connect(mongoConnectionUri, { useMongoClient: true })
.then(() => {
// eslint-disable-next-line no-param-reassign
server.app.db = Models;
});
next();
};
It is accessed as such, and works fine:
module.exports.doSomething = async (request, reply) => {
const Models = request.server.app.db;
const data = await Models.persistenceMethod();
reply(data);
}
However, I am struggling to mock persistenceMethod(). I tried with Sinon or monkey-patching:
test('retrieves data', async () => {
server.app.db = {
persistenceMethod: () =>
// eslint-disable-next-line no-unused-vars
new Promise((resolve, reject) => resolve({ foo: 'bar' }))
};
const expectedPayload = [ { foo: 'bar' } ];
const response = await server.inject({'GET', '/api/getFoo'});
const payload = response.payload;
expect(response.statusCode).to.equal(200);
expect(JSON.parse(payload)).to.deep.equal(expectedPayload);
});
But it seems that server.app.db and request.server.app.db are two different objects altogether. I tried monkey-patching server.root.app.db as well, but to no avail.
Is there a way to stub the db object, or do I need to use proxyquire to inject a fake database plugin?

Answer 1

I still haven't found the solution to the original problem, but instead, I am injecting a mock database plugin using Glue:
exports.register = (server, options, next) => {
// eslint-disable-next-line no-param-reassign
server.app.db = {
persistenceMethod: () => new Promise((resolve, reject) => {
resolve({foo: 'bar'});
})};
next();
};
I would prefer not touching the manifest for Glue, but it's the best I can do for now.