private IUsersConfig CreateUserConfig(string xml)
        {
            var config  = CreateConfig(xml);
            var factory = new UsersConfigFactory();

            return(factory.Create(config));
        }
        public void Create_PassNullConfig_ThrowsArgumentNullException()
        {
            var factory = new UsersConfigFactory();

            Assert.Throws <ArgumentNullException>(() => factory.Create(null));
        }