public void GetByMail_Flow_User()
        {
            var mail  = "*****@*****.**";
            var users = new List <User> {
                new User {
                    Mail = mail
                }
            }.AsQueryable();

            var mockSet = MockHelper.MockDbSet(users);

            var result = UserExtension.GetByMail(mockSet.Object, mail);

            Assert.AreEqual(mail, result.Mail);
        }