@Test
public void testSingleSubpolygon() throws ParseException {

  String wkt = "POLYGON ((0 0, 0 10, 10 10, 10 0, 0 0))";
  WKTReader wktReader = new WKTReader();
  Geometry geometry = wktReader.read(wkt);
  Geometry actual = convertSubpolygonsToEnvelopes.apply(geometry, new GeometryOperator.Context());
  assertThat(actual, is(geometry));
}