sinon stub is not working - testing

Question

I'm quiet new into testing and I don't seem to succeed to succesfully stub a function. I'm trying to stub the connection to the database, but it keep's contacting it, instead of using the result from the stub:
Here's the function:
var self = module.exports = {
VerifyAuthentication: function (data){
var deferred = q.defer()
if(typeof(data.email)=='undefined'){
deferred.reject({data:{},errorcode:"",errormessage:"param 'email' is mandatory in input object"})
}else{
if(typeof(data.password)=='undefined'){
deferred.reject({data:{},errorcode:"",errormessage:"param 'password' is mandatory in input object"})
}else{
var SqlString = "select id, mail, password, origin from tbl_user where mail = ?"
var param = [data.email]
self.ExecuteSingleQuery(SqlString, param).then(function(results){
if(results.length > 0)
{
if (results[0].password == data.password)
{
deferred.resolve({data:{"sessionId":results[0].id},errorcode:"",errormessage:""})
}else{
deferred.reject({data:{},errorcode:"",errormessage:"bad password"})
}
}else{
deferred.reject({data:{},errorcode:"",errormessage:"unknown user"})
}
})
}
}
return deferred.promise
},
ExecuteSingleQuery: function (queryString, parameters){
var deferred = q.defer()
var connection = connect()
connection.query(queryString, parameters, function (error, results, fields){
if(error){ deferred.reject(error)};
deferred.resolve(results)
});
return deferred.promise
},
And here's the test:
var dbconnection = require('../lib/dbConnection.js')
describe("VerifyAuthentication", function(){
it("_Returns DbResult object when user name and password match", function(){
var expectedResult = {data:{"sessionKey":"b12ac0a5-967e-40f3-8c4d-aac0f98328b2"},errorcode:"",errormessage:""}
stub = sinon.stub(dbconnection, 'ExecuteSingleQuery').returns(Promise.resolve(expectedResult))
return dbconnection.VerifyAuthentication({email:"correct#adres.com",password:"gtffr"}).then((result)=>{
expect(result.data.sessionId).to.not.be.undefined
expect(result.errorcode).to.not.be.undefined
expect(result.errormessage).to.not.be.undefined
stub.restore()
})
})
})
I always got an error 'unknown user', which is normal, because the user is indeed not in the database. However, I want to stub the 'ExecuteSingleQuery' function, avoiding it to connect to DB.

Answer 1

I have fixed a couple of issues in your code and posting the corrected files below.
dbConnection.js
var self = module.exports = {
VerifyAuthentication: function (data) {
var deferred = q.defer();
if (typeof (data.email) == 'undefined') {
deferred.reject({
data: {},
errorcode: '',
errormessage: "param 'email' is mandatory in input object"
});
} else {
if (typeof (data.password) == 'undefined') {
deferred.reject({
data: {},
errorcode: '',
errormessage: "param 'password' is mandatory in input object"
});
} else {
var SqlString = 'select id, mail, password, origin from tbl_user where mail = ?';
var param = [data.email];
self.ExecuteSingleQuery(SqlString, param).then(function (results) {
if (results.length > 0) {
if (results[0].password === data.password) {
deferred.resolve({
data: {
'sessionId': results[0].id
},
errorcode: '',
errormessage: ''
});
} else {
deferred.reject({
data: {},
errorcode: '',
errormessage: 'bad password'
});
}
} else {
deferred.reject({
data: {},
errorcode: '',
errormessage: 'unknown user'
});
}
});
}
}
return deferred.promise;
},
ExecuteSingleQuery: function (queryString, parameters) {
var deferred = q.defer();
var connection = connect();
connection.query(queryString, parameters, function (error, results, fields) {
if (error) {
deferred.reject(error);
}
deferred.resolve(results);
});
return deferred.promise;
}
};
dbConnection.test.js
describe('VerifyAuthentication', function () {
it('Returns DbResult object when user name and password match', function () {
var expectedResult = [{
id: '123',
password: 'gtffr'
}];
const stub = sinon.stub(dbconnection, 'ExecuteSingleQuery').resolves(expectedResult);
return dbconnection.VerifyAuthentication({
email: 'correct#adres.com',
password: 'gtffr'
}).then((result) => {
expect(result.data.sessionId).to.not.be.undefined;
expect(result.errorcode).to.not.be.undefined;
expect(result.errormessage).to.not.be.undefined;
stub.restore();
});
});
});
I am outlining the problematic parts below:
The expectedResult variable had a wrong type of value. In the
self.ExecuteSingleQuery() implementation you check for an array with length > 0. The fixed result returned by the stub, was an object instead of an array and this is why it returned the unknown user exception
The array should contain an object with { id: 'xxx', password: 'gtffr' } attributes. Password is validated against the one used by the dbconnection.VerifyAuthentication({email:"correct#adres.com",password:"gtffr"}) call
Finally, I have changed the stub statement to resolve instead of return as shown here const stub = sinon.stub(dbconnection, 'ExecuteSingleQuery').resolves(expectedResult); - this is the preferred method of resolving a promise