public static void int64()
{
Random64 rng = new Random64(13255);
for (int i = 0; i < 64; i++)
{
long x = rng.NextLong();
long y = rng.NextLong();
Assert.AreEqual(_gcd(x, y), maxmath.gcd(x, y));
Assert.AreEqual(0, x % _gcd(x, y));
Assert.AreEqual(0, y % _gcd(x, y));
}
}