javascript does not enter in then block in test file

in the name of GOD i wrote bellow code for product model for a shopping web app :

var mongoose = require('mongoose');
var Category = require('./category')
var q = require('q');

productSchema ={
    'name' : {type : String ,
        required : true},
    'price' :{type : Number ,
        required: tru`enter code here`e},
    'pictures' : [{type : String , default :'http://ift.tt/2brmrJX'}],
    'Category' : Category.categorySchema

};

var Product = new mongoose.Schema(productSchema);
var productModel = mongoose.model('productModel' ,Product ,'product');

//method
exports.insert = function (doc) {
    var document = new  productModel(doc);
    var final = q.defer();
    document.save(function (error) {
        if(error)
            final.reject(false);
        else
            final.resolve(true);
    });
    return final.promise;
};

and i wrote a test for this program :

var mongoose = require('mongoose');
var product = require('./product');
var assert = require('assert');
var config = require('./config');
var q = require('q');

mongoose.connect(config.testUri);

describe('product Test:' , function () {
    var testInput = {'name' : 'calculase one' , 'price': 50 , 'pictures':['http://ift.tt/2bgnQGL'] , Category:{'_id' : 'One' , "parent" : "Calculase" , "ansestors" : ["One" , "Calculase" , "Books"]}};
    var result = product.insert(testInput);
    it('inserting into collection. ' , function () {
        result.then(function (resultDoc) {
            assert.equal(resultDoc.name ,true);
        })
    });

my test is passing.even I connect to database or not connect.I discover that my program does not enter in "then" scope and assert.equal method does not run.please guide me to solve this Problem. thank!