public void Test_S2Cap_AddNonEmptyCapToEmptyCap()
{
S2Cap empty = S2Cap.Empty;
S2Cap non_empty_cap = new(new S2Point(1, 0, 0), S1Angle.FromDegrees(10));
empty = empty.AddCap(non_empty_cap);
Assert.Equal(non_empty_cap.Area(), empty.Area());
}