"content_ca",
        "content_ckb-iq",
        "content_cs",
        "content_da",
        "content_de",
        "content_el",
        "content_en",
        "content_en-ie",
        "content_es",
        "content_et",
        "content_eu",
        "content_fa",
        "content_fi",
        "content_fr",
        "content_gl",
        "content_gu",
        "content_he",

        "content_ca",
        "content_ckb-iq",
        "content_cs",
        "content_da",
        "content_de",
        "content_el",
        "content_en",
        "content_en-ie",
        "content_es",
        "content_et",
        "content_eu",
        "content_fa",
        "content_fi",
        "content_fr",
        "content_gl",
        "content_gu",
        "content_he",

        "content_ca",
        "content_ckb-iq",
        "content_cs",
        "content_da",
        "content_de",
        "content_el",
        "content_en",
        "content_en-ie",
        "content_es",
        "content_et",
        "content_eu",
        "content_fa",
        "content_fi",
        "content_fr",
        "content_gl",
        "content_gu",
        "content_he",

      for (List<Integer> contents : SAMPLE_INPUTS) {
        for (int toRemove = 0; toRemove < 10; toRemove++) {
          assertEquals(
              contents.contains(toRemove) && EVEN.apply(toRemove),
              filter(createUnfiltered(contents), EVEN).remove(toRemove));
        }
      }
    }

    public void testContains() {
      for (List<Integer> contents : SAMPLE_INPUTS) {

    return new MinimalCollection<>(Object.class, true, contents);
  }

  // TODO: use this
  public static <E extends @Nullable Object> MinimalCollection<E> ofClassAndContents(
      Class<? super @NonNull E> type, E... contents) {
    return new MinimalCollection<>(type, true, contents);
  }

  private final E[] contents;
  private final Class<? super @NonNull E> type;

        "filter" : ["lowercase"]
      },
      "contents_analyzer" : {
        "type" : "custom",
        "tokenizer" : "fess_japanese_normal",
        "char_filter" : ["mapping_char"],
        "filter" : ["lowercase", "stopword_en_filter", "pos_filter", "content_length_filter", "limit_token_count_filter"]
      },
      "contents_reading_analyzer" : {
        "type" : "custom",

        "filter" : ["lowercase"]
      },
      "contents_analyzer" : {
        "type" : "custom",
        "tokenizer" : "fess_japanese_normal",
        "char_filter" : ["mapping_char"],
        "filter" : ["lowercase", "stopword_en_filter", "pos_filter", "content_length_filter", "limit_token_count_filter"]
      },
      "contents_reading_analyzer" : {
        "type" : "custom",

	}

	var contents []ItemContent
	if err := tx.Find(&contents).Error; err != nil {
		t.Errorf("failed to find contents, got error: %v", err)
	}
	if len(contents) != 3 {
		t.Errorf("expected %d contents, got %d", 3, len(contents))
	}

	// test delete
	if err := tx.Model(&item).Association("Contents").Unscoped().Delete(&contents[0]); err != nil {
		t.Errorf("failed to delete Contents, got error: %v", err)
	}

        return new TreeSet<E>(contents);
      }
    },
    UnmodifiableSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {
        return Collections.unmodifiableSet(new HashSet<E>(contents));
      }
    },
    SynchronizedSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {

        return new TreeSet<E>(contents);
      }
    },
    UnmodifiableSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {
        return Collections.unmodifiableSet(new HashSet<E>(contents));
      }
    },
    SynchronizedSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {