Using Sinon to stub chained Mongoose calls - node.js

Question

I get how to stub Mongoose models (thanks to Stubbing a Mongoose model with Sinon), but I don't quite understand how to stub calls like:
myModel.findOne({"id": someId})
.where("someBooleanProperty").equals(true)
...
.exec(someCallback);
I tried the following:
var findOneStub = sinon.stub(mongoose.Model, "findOne");
sinon.stub(findOneStub, "exec").yields(someFakeParameter);
to no avail, any suggestions?

Answer 1

I've solved it by doing the following:
var mockFindOne = {
where: function () {
return this;
},
equals: function () {
return this;
},
exec: function (callback) {
callback(null, "some fake expected return value");
}
};
sinon.stub(mongoose.Model, "findOne").returns(mockFindOne);

Answer 2

Take a look to sinon-mongoose. You can expects chained methods with just a few lines:
sinon.mock(YourModel).expects('findOne')
.chain('where').withArgs('someBooleanProperty')
.chain('exec')
.yields(someError, someResult);
You can find working examples on the repo.
Also, a recommendation: use mock method instead of stub, that will check the method really exists.

Answer 3

Another way is to stub or spy the prototype functions of the created Query (using sinon):
const mongoose = require('mongoose');
sinon.spy(mongoose.Query.prototype, 'where');
sinon.spy(mongoose.Query.prototype, 'equals');
const query_result = [];
sinon.stub(mongoose.Query.prototype, 'exec').yieldsAsync(null, query_result);

Answer 4

If you use Promise, you can try sinon-as-promised:
sinon.stub(Mongoose.Model, 'findOne').returns({
exec: sinon.stub().rejects(new Error('pants'))
//exec: sinon.stub(). resolves(yourExepctedValue)
});

Answer 5

I use promises with Mongoose and stub the methods like this:
const stub = sinon.stub(YourModel, 'findById').returns({
populate: sinon.stub().resolves(document)
})
Then I can call it like:
const document = await YourModel.findById.populate('whatever');

Answer 6

Using Multiple mongoose method stub using below code.
Service code
models.Match.findOne({ where: { id: ChangeInningInputType.id } })
.then((match) => {
if (!match) {
throw Error('Match not found');
}
models.Match.update(
{ inning: ChangeInningInputType.inning },
{ where: { id: ChangeInningInputType.id } },
);
return resolve(match);
})
.catch((error) => {
return reject(error);
});
Testcase code
it('Success test case for inning update', async () => {
const bulkCreateStub = sinon
.stub(models.Match, 'findOne')
.resolves(inningResponse);
const updateStub = sinon
.stub(models.Match, 'update')
.resolves(inningResponse);
const aa = await changeInning(
{},
{
ChangeInningInputType: inningRequest,
},
);
console.log('updateStub===>', updateStub);
expect(updateStub.calledOnce).to.equal(true);
expect(bulkCreateStub.calledOnce).to.equal(true);
});