public void testRoundingError()
        {
            var a = new S2Point(-0.9190364081111774, 0.17231932652084575, 0.35451111445694833);
            var b = new S2Point(-0.92130667053206, 0.17274500072476123, 0.3483578383756171);
            var c = new S2Point(-0.9257244057938284, 0.17357332608634282, 0.3360158106235289);
            var d = new S2Point(-0.9278712595449962, 0.17397586116468677, 0.32982923679138537);

            assertTrue(S2Loop.IsValidLoop(new List <S2Point>(new[] { a, b, c, d })));
        }