@Test
  void testDefaultLanguages() {
    var planetiler = Planetiler.create(Arguments.of("languages", "default,en"))
      .setDefaultLanguages(List.of("jbo", "tlh"));
    var translations = planetiler.translations();
    assertTrue(translations.careAboutLanguage("jbo"));
    assertTrue(translations.careAboutLanguage("tlh"));
    assertTrue(translations.careAboutLanguage("en"));
    assertFalse(translations.careAboutLanguage("fr"));
  }
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