Testing saves data in database - mysql

Question

Hi I am trying to run mocha and chai test to test my node js router, which saves a user in mysql database and then returns the same array back.
The problem I am facing at the moment is that I would not like to save the information in the database when I run it from local and when I use a continious integration software like travis/Ci the test fails since there is no database connection. I would like to know how can I test the database saving with the current without actually saving to the database.
Basically meaning having a fake virtual database to save or returning save.
I read that sinon.js can help but I am quite not sure on how to use it.
Here is my code
var expect = require('chai').expect;
var faker = require('faker');
const request = require('supertest');
const should = require('should');
const sinon = require('sinon');
const helper = require('../../models/user');
describe('POST /saveUser',()=>{
it('should save a new user',(done)=>{
var fake =
request(app)
.post('/saveUser')
.send({
Owner : faker.random.number(),
firstname : faker.name.firstName(),
lastname : faker.name.lastName(),
email:faker.internet.email(),
password : faker.random.number(),
token : faker.random.uuid()
})
.expect(200)
.expect((res)=>{
expect(res.body.firstname).to.be.a("string");
expect(res.body.lastname).to.be.a("string");
expect(res.body.Owner).to.be.a("number");
})
.end(done);
});
});
This is the router
router.post('/saveUser',(req,res,next)=>{
saveUser(req.body).then((result)=>{
return res.send(req.body);
}).catch((e)=>{
return res.send('All info not saved');
});
});
And here is the model
saveUser = (userinfo) => new Promise((resolve,reject)=>{
db.query('INSERT INTO user SET ?',userinfo,function(error,results,fields){
if(error){
reject();
}else{
resolve(userinfo);
}
})
});

Answer 1

What you are describing is a stub. With sinon you can stub methods and call fake methods instead like this:
sinon.stub(/* module that implements saveUser */, 'saveUser').callsFake(() => Promise.resolve());