@Test
  void testBadRelation() throws Exception {
    // this threw an exception in OsmMultipolygon.build
    OsmXml osmInfo = TestUtils.readOsmXml("bad_spain_relation.xml");
    List<OsmElement> elements = convertToOsmElements(osmInfo);

    var results = runWithOsmElements(
      Map.of("threads", "1"),
      elements,
      (in, features) -> {
        if (in.hasTag("landuse", "forest")) {
          features.polygon("layer")
            .setZoomRange(12, 14)
            .setBufferPixels(4);
        }
      }
    );

    assertEquals(11, results.tiles.size());
  }
In-memory tests with fake data and profiles to ensure all features work end-to-end.
planetiler-core/src/test/java/com/onthegomap/planetiler/PlanetilerTests.java