assertThrows(NullPointerException.class, () -> new PercentEscaper(null, false));
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg = "Alphanumeric characters are always 'safe' and should not be explicitly specified";
    IllegalArgumentException expected =

    assertThrows(NullPointerException.class, () -> new PercentEscaper(null, false));
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg = "Alphanumeric characters are always 'safe' and should not be explicitly specified";
    IllegalArgumentException expected =

        } catch (final IOException e) {
            return StringUtil.EMPTY; // empty
        }
    }

    /**
     * Gets the maximum size for alphanumeric terms from configuration.
     *
     * @return the maximum alphanumeric term size
     */
    protected int getMaxAlphanumTermSize() {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

crawler.document.use.site.encoding.on.english=false
# Whether to append data to documents.
crawler.document.append.data=true
# Whether to append filename to documents.
crawler.document.append.filename=false
# Maximum size of alphanumeric terms in documents.
crawler.document.max.alphanum.term.size=20
# Maximum size of symbol terms in documents.
crawler.document.max.symbol.term.size=10
# Whether to remove duplicate terms in documents.

    boolean isCrawlerDocumentAppendFilename();

    /**
     * Get the value for the key 'crawler.document.max.alphanum.term.size'. <br>
     * The value is, e.g. 20 <br>
     * comment: Maximum size of alphanumeric terms in documents.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getCrawlerDocumentMaxAlphanumTermSize();

    /**