public void Test_S2ShapeIndexRegion_GetCapBound()
{
var id = S2CellId.FromDebugString("3/0123012301230123012301230123");
// Add a polygon that is slightly smaller than the cell being tested.
MutableS2ShapeIndex index = new();
index.Add(NewPaddedCell(id, -kPadding));
S2Cap cell_bound = new S2Cell(id).GetCapBound();
S2Cap index_bound = index.MakeS2ShapeIndexRegion().GetCapBound();
Assert.True(index_bound.Contains(cell_bound));
// Note that S2CellUnion.GetCapBound returns a slightly larger bound than
// S2Cell.GetBound even when the cell union consists of a single S2CellId.
Assert.True(index_bound.RadiusAngle() <= 1.00001 * cell_bound.RadiusAngle());
}