@Test
  void testCombineMultiPoint() throws Exception {
    var results = runWithReaderFeatures(
      Map.of("threads", "1"),
      List.of(
        // merge same group:
        newReaderFeature(z14Point(0, 0), Map.of("group", "1")),
        newReaderFeature(newMultiPoint(
          z14Point(1, 1),
          z14Point(2, 2)
        ), Map.of("group", "1")),
        // don't merge - different group:
        newReaderFeature(z14Point(3, 3), Map.of("group", "2"))
      ),
      (in, features) -> features.point("layer")
        .setZoomRange(14, 14)
        .setBufferPixels(0)
        .inheritAttrFromSource("group"),
      (layer, zoom, items) -> FeatureMerge.mergeMultiPoint(items)
    );

    assertSubmap(sortListValues(Map.of(
      TileCoord.ofXYZ(Z14_TILES / 2, Z14_TILES / 2, 14), List.of(
        feature(newMultiPoint(
          newPoint(0, 0),
          newPoint(1, 1),
          newPoint(2, 2)
        ), Map.of("group", "1")),
        feature(newPoint(3, 3), Map.of("group", "2"))
      )
    )), sortListValues(results.tiles));
  }
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