public void UserEquality()
        {
            // Arrange
            var user1 = new User("user1")
            {
                Key = 1
            };
            var user2 = new User("user2")
            {
                Key = 1
            };
            var user3 = new User("user2")
            {
                Key = 3
            };

            // Assert
            Assert.True(user1 == user2);
            Assert.True(user1.Equals(user2));
            Assert.True(user3 != user2);
            Assert.True(user1.GetHashCode() == user2.GetHashCode());
        }