[2.0] Implement ==?

[high6]

class test
        {
            public int i = 0;
            static  bool EqualsHelper(test a, test b)
            {
                return (a.i == b.i);
            }
            static bool Equals(test a, test b)
            {
                return ((a == b) || (((a != null) && (b != null)) && EqualsHelper(a, b)));
            }
            public static bool operator !=(test a, test b)
            {
                return !Equals(a, b);
            }
            public static bool operator ==(test a, test b)
            {
                return Equals(a, b);
            }
            public test(int a)
            {
                i = a;
            }
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            if (new test(1) != null)
            {
                if (new test(1) == new test(1))
                {

                }
            }
        }

I keep getting a stack overflow, yet this is how System.String is setup.

How do you correctly implement ==?