How can I unit test async database calls without changing the route? - node.js

Question

So I have a route with a database call in a separate file:
module.exports = (req, res) => {
const sql = `SELECT Topic FROM surveys WHERE ID="${req.params.id}"`;
model.connection.query(sql, (err, result) => {
if (err) res.status(500).send(err);
res.send(result);
});
};
In my test file, I create fake req and res objects to test different inputs:
const req = {
body: {},
params: {
id: '',
}
};
const res = {
message: '',
stat: 200,
send(arg) {
this.message = arg;
},
status(number) {
this.stat = number;
return this;
}
};
And call it in every test:
it('Should return status 200 if parameter is a number string', () => {
req.params.id = '1';
getTopic(req, res);
chai.expect(res.stat).to.equal(200);
});
My question is, how can I test it asynchronously, without affecting my route?
I've seen Mocha documentation explaining this, but they require a callback in a function.
it('Should return status 200 if parameter is a number string', (done) => {
req.params.id = '1';
getTopic(req, res); // Cannot give any callback
chai.expect(res.stat).to.equal(200);
done(); //Doesn't work
});
I also tried using async/await, but it didn't work (I lack knowledge of how to use it, maybe that's why)
it('Should return status 200 if parameter is a number string', async () => {
req.params.id = '1';
await getTopic(req, res);
chai.expect(res.stat).to.equal(200);
});
And I've seen this question, and didn't help at all: unit testing express route with async callback