private <K extends Comparable<? super K>, V extends List<?>> Map<K, ?> sortListValues(Map<K, V> input) {
    Map<K, List<?>> result = new TreeMap<>();
    for (var entry : input.entrySet()) {
      List<?> sorted = entry.getValue().stream().sorted(Comparator.comparing(Object::toString)).toList();
      result.put(entry.getKey(), sorted);
    }
    return result;
  }
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