public void UserManagementLogic_UserExists_RepositoryReturnsNull_ReturnsFalse()
        {
            Mock <IConfigurationRepository> configurationRepository = new Mock <IConfigurationRepository>();

            configurationRepository.Setup(x => x.Get <AuthenticablePrincipal>(It.IsAny <Guid>())).Returns((AuthenticablePrincipal)null);

            UserManagementLogic userManagementLogic = new UserManagementLogic(configurationRepository.Object, new AuthorizeInitialSetup(configurationRepository.Object));

            bool result = userManagementLogic.UserExists(Guid.NewGuid());

            Assert.IsFalse(result);
        }