Optional<Charset> charset = ((MediaType) field.get(null)).charset();
      if (field.getName().endsWith("_UTF_8")) {
        assertThat(charset).hasValue(UTF_8);
      } else {
        assertThat(charset).isAbsent();
      }
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  public void testConstants_areUnique() {
    assertThat(getConstants()).containsNoDuplicates();
  }

  @J2ktIncompatible

    assertThat(tryFind(list, equalTo("pants"))).hasValue("pants");
    assertThat(tryFind(list, Predicates.alwaysTrue())).hasValue("cool");
    assertThat(tryFind(list, Predicates.alwaysFalse())).isAbsent();
    assertCanIterateAgain(list);
  }

  private static class TypeA {}

  private interface TypeB {}

  private static class HasBoth extends TypeA implements TypeB {}

    assertThat(tryFind(list, equalTo("pants"))).hasValue("pants");
    assertThat(tryFind(list, Predicates.alwaysTrue())).hasValue("cool");
    assertThat(tryFind(list, Predicates.alwaysFalse())).isAbsent();
    assertCanIterateAgain(list);
  }

  private static class TypeA {}

  private interface TypeB {}

  private static class HasBoth extends TypeA implements TypeB {}

  public void testTryFind_alwaysFalse_isPresent() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, Predicates.alwaysFalse())).isAbsent();
    assertFalse(iterator.hasNext());
  }

  public void testTransform() {
    Iterator<String> input = asList("1", "2", "3").iterator();
    Iterator<Integer> result =
        Iterators.transform(

  public void testTryFind_alwaysFalse_isPresent() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, Predicates.alwaysFalse())).isAbsent();
    assertFalse(iterator.hasNext());
  }

  public void testTransform() {
    Iterator<String> input = asList("1", "2", "3").iterator();
    Iterator<Integer> result =
        Iterators.transform(