public void AccessToken_AddAnAccessToken_ShouldAddCorrectly()
        {
            var data = new List <AccessToken>().AsQueryable();

            var mock        = new Mock <DbSet <AccessToken> >();
            var mockContext = new Mock <Models.Models.Database>();

            mockContext.Setup(m => m.AccessTokens).Returns(mock.Object);

            AccessTokenService accTokService = new AccessTokenService(mockContext.Object);
            AccessToken        accToken      = new AccessToken()
            {
                Device = new Device()
                {
                    Id = Guid.NewGuid(), LastRequestDateTime = DateTime.Now
                },
                UniqueAccesToken = Guid.NewGuid().ToString("D"),
                CreatedDateTime  = DateTime.Now
            };

            accTokService.AddAccessToken(accToken);

            mock.Verify(m => m.Add(It.IsAny <AccessToken>()), Times.Once());
            mockContext.Verify(m => m.SaveChanges(), Times.Once());
        }