public void UpdateAdv ( Adv adv )
		{
			if (adv.Id==0)
			{
				throw new ArgumentException("UpdateAdv id==0");
			}
			Advs.Attach(adv);
			Entry(adv).State=EntityState.Modified;
		} 
		public DbDataContextMock()
		{
			Advs =new List<Adv>();
			Companies = new List<Company>();
			DeviceUsers = new List<DeviceUser> ();
			Views = new List<AdvView>();
			CompanyUsers=new List<CompanyUser>();
			CompanyUserSessions = new List<CompanyUserSession>();
			var testAdv = new Adv () {
				Name = "apple" ,
				Link = "http://www.apple.com",
				Title = "Apple Inc.",
				Description = "empty description - apple",
				PhotoId = 1 ,
				DeviceUsers = new List<DeviceUser> ()
			};
			var testAdv1 = new Adv () {
				Name = "sony" ,
				Link = "http://sony.com" ,
				Title = "Sony" ,
				Description = "empty description - sony" ,
				PhotoId = 2 ,
				DeviceUsers = new List<DeviceUser> ()
			};
			var testUser = new DeviceUser () {
				DeviceId = "d1" ,
				Login = "******" ,
				Password = "******" ,
				Advs = new List<Adv> () ,
				Companies = new List<Company> ()
			};
			var testCompany = new Company () {
				ApiKey = "company1" ,
				Name = "company1" ,
				Advs = new List<Adv> () ,
				DeviceUsers = new List<DeviceUser> ()
			};
			var companyUser = new CompanyUser()
			{
				Login = "******",
				Company = testCompany,
				CompanyId = testCompany.Id,
				Password = AuthUtil.EncodePassword("admin")
			};


			testCompany.Advs.Add ( testAdv );
			testCompany.DeviceUsers.Add ( testUser );
			testCompany.Advs.Add(testAdv1);

			this.AddAdv ( testAdv );
			this.AddAdv(testAdv1);
			this.AddDeviceUser ( testUser );
			this.AddCompany ( testCompany );
			this.AddCompanyUser(companyUser);
		}
		public void AddAdv(Adv adv)
		{
			var maxAdv = Advs.OrderByDescending ( a => a.Id ).FirstOrDefault ();
			adv.Id = maxAdv != null ? maxAdv.Id + 1 : 1;
			Advs.Add ( adv );
		}
		public void UpdateAdv(Adv adv)
		{
			var obj = Advs.First ( a => a.Id == adv.Id );
			obj = adv;
		}
		public void AddAdv ( Adv adv )
		{
			Advs.Add(adv);
		}