assertThat(Chars.contains(ARRAY234, (char) 2)).isTrue();
    assertThat(Chars.contains(ARRAY234, (char) 3)).isTrue();
    assertThat(Chars.contains(ARRAY234, (char) 4)).isTrue();
  }

  public void testIndexOf() {
    assertThat(Chars.indexOf(EMPTY, (char) 1)).isEqualTo(-1);
    assertThat(Chars.indexOf(ARRAY1, (char) 2)).isEqualTo(-1);
    assertThat(Chars.indexOf(ARRAY234, (char) 1)).isEqualTo(-1);

    assertEquals(s, xmlEscaper.escape(s));

    // Test ASCII control characters.
    for (char ch = 0; ch < 0x20; ch++) {
      if (ch == '\t' || ch == '\n' || ch == '\r') {
        // Only these whitespace chars are permitted in XML,
        if (shouldEscapeWhitespaceChars) {
          assertEscaping(xmlEscaper, "&#x" + Integer.toHexString(ch).toUpperCase() + ";", ch);
        } else {
          assertUnescaped(xmlEscaper, ch);

        final int[] values = getCrawlerDocumentCharsAsArray(QUERY_HIGHLIGHT_BOUNDARY_CHARS, getQueryHighlightBoundaryChars());
        final char[] chars = new char[values.length];
        for (int i = 0; i < values.length; i++) {
            chars[i] = (char) values[i];
        }
        return chars;
    }

    String getQueryHighlightTerminalChars();

    default int[] getQueryHighlightTerminalCharsAsArray() {

crawler.document.duplicate.term.removed=false
# Unicode space characters for document parsing.
crawler.document.space.chars=u0009u000Au000Bu000Cu000Du001Cu001Du001Eu001Fu0020u00A0u1680u180Eu2000u2001u2002u2003u2004u2005u2006u2007u2008u2009u200Au200Bu200Cu202Fu205Fu3000uFEFFuFFFDu00B6
# Unicode full stop characters for document parsing.
crawler.document.fullstop.chars=u002eu06d4u2e3cu3002
# Encoding for crawling data.
crawler.crawling.data.encoding=UTF-8

    String CRAWLER_DOCUMENT_SPACE_CHARS = "crawler.document.space.chars";

    /** The key of the configuration. e.g. u002eu06d4u2e3cu3002 */
    String CRAWLER_DOCUMENT_FULLSTOP_CHARS = "crawler.document.fullstop.chars";

    /** The key of the configuration. e.g. UTF-8 */
    String CRAWLER_CRAWLING_DATA_ENCODING = "crawler.crawling.data.encoding";