models_computer.js

"use strict";
module.exports = function(sequelize, DataTypes) {
  var computers = sequelize.define("computers", {
    domain: DataTypes.STRING
  }, {
    classMethods: {
      exists: function(d){
        return computers.count({where:{domain:d}}).then(function(count){
          if(count>0){
            return true;
          }else{
            return false;
          }
        });
      }
    },
    instanceMethods:{

    }
  });
  return computers;
};

test_computer.js

var assert = require("assert");
var models = require('../models');

describe('on computers model call', function(){
	describe('#exists(d)', function(){
		it('should return true if computer exists else return false', function(done){
			models.computers.exists('test').then(function(exists){
				console.log(exists);
				assert.equal(true, exists);
				done();
			});
		});
	});
});