Mocha: Promises timing out no matter the time limit - node.js

Question

I'm working on an interview project for which I have to add an endpoint that lets me POST an array of products (listings) and it should create them (MongoDB + Mongoose) or update them accordingly. The problem is I'm clearly not dealing with Promises properly and I'm getting a timeout on my test.
Here's the spec:
it.only('should create listings or update them if they already exist, incrementing the quantity with the difference ' +
'between the current sold_quantity and the initial_sold_quantity', (done) => {
var iPhone = { ... };
var samsung = { ... };
request(app).post('/listings/myEndpoint').send([iPhone, samsung]).expect(200, {
created: 1,
updated: 1
}, done);
});
exports.myEndpoint = (req, res) => {
var listings = req.body;
var created, updated = 0;
listings.forEach(reqListing => {
Listing.findOne({ listing_id: reqListing.listing_id })
.then(foundListing => {
if (!foundListing) {
var newListing = reqListing;
newListing.initial_sold_quantity = newListing.sold_quantity;
Listing.create(newListing);
created++;
} else {
var newQuantity = reqListing.sold_quantity - foundListing._doc.initial_sold_quantity;
if (foundListing._doc.quantity != newQuantity) {
foundListing._doc.quantity = newQuantity;
foundListing.save();
updated++;
}
}
});
return {
created: created,
updated: updated
};
});
};
THINGS I'VE TRIED:
Giving it more time. I tried changing the default timeout for Mocha tests but it doesn't really matter if it's 2 seconds or 20, it'll still timeout.
Isolating the update vs the creation. Really doesn't matter either if I'm only updating a product or if I'm only creating one, it'll still timeout.
Removing the logic. As far as I've checked it doesn't really matter what happens inside the if/else blocks because it'll still give me a timeout. So even if the code looks like this:
exports.myEndpoint = (req, res) => {
var listings = req.body;
var created, updated = 0;
listings.forEach(reqListing => {
Listing.findOne({ listing_id: reqListing.listing_id })
.then(foundListing => {
if (!foundListing) {
console.log("creating");
} else {
console.log("updating");
}
});
return {
created: created,
updated: updated
};
});
};
it'll still timeout.

Answer 1

After asking some questions in the Nodeiflux Discord server I managed to find a solution, maybe not the prettiest because it doesn't make use of async/await but I'm not supposed to change the style of the project too much so I'll leave it without async/await.
First, the silly problem which came after fixing the post's question:
var created = 0, updated = 0;
instead of not initializing created.
Second, making use of forEach with Promises inside didn't make too much sense because it would discard whatever was returning inside so I put the return outside the forEach clause and changed the forEach iteration for a map instead. I also made use of Promise.all() to get all promises to resolve before returning:
exports.upsert = (req, res) => {
var listings = req.body;
var created = 0, updated = 0;
var allowedArrayLength = 50;
return Promise.all(listings.map(reqListing =>
Listing.findOne({
listing_id: reqListing.listing_id
})
.then(foundListing => {
if (!foundListing) {
createListing(reqListing);
created++;
} else {
var prevQuantity = foundListing.quantity;
if (updateListing(reqListing, foundListing).quantity > prevQuantity) {
updated++;
}
}
})
)).then(() => ({ created: created, updated: updated }));
};