public void NearestAboveTest()
{
Assert.Equal(1UL, ZCurve.NearestAbove(0, 0));
Assert.Equal(2UL, ZCurve.NearestAbove(0, 1));
Assert.Equal(4UL, ZCurve.NearestAbove(0, 2));
Assert.Equal(8UL, ZCurve.NearestAbove(0, 3));
Assert.Equal(1UL << 31, ZCurve.NearestAbove(0, 31));
Assert.Equal(1UL << 63, ZCurve.NearestAbove(0, 63));
Assert.Equal(3UL, ZCurve.NearestAbove(3, 0));
Assert.Equal(3UL, ZCurve.NearestAbove(3, 1));
Assert.Equal(6UL, ZCurve.NearestAbove(3, 2));
Assert.Equal(9UL, ZCurve.NearestAbove(3, 3));
Assert.Equal(18UL, ZCurve.NearestAbove(3, 4));
Assert.Equal(66UL, ZCurve.NearestAbove(3, 6));
Assert.Equal(129UL, ZCurve.NearestAbove(3, 7));
Assert.Equal((1UL << 31) + 1, ZCurve.NearestAbove(3, 31));
Assert.Equal((1UL << 63) + 1, ZCurve.NearestAbove(3, 63));
// TODO More
}