public void TestGetAllFollower()
        {
            IEnumerable <User> ienumableUsers = new List <User>()
            {
                user, userSecond
            };

            mockFollowRepository.Setup(x => x.GetAllFollower(It.IsAny <string>())).Returns(ienumableUsers);
            var followService = new FollowService(mockFollowRepository.Object);
            IEnumerable <User> ienumableReturn = followService.GetAllFollower("5d111299f3b75e0001f4ed78");
            User userActual = ienumableReturn.FirstOrDefault();

            Assert.AreEqual(userActual, user);
        }