assertEquals("", Strings.commonSuffix("", ""));
    assertEquals("", Strings.commonSuffix("abc", ""));
    assertEquals("", Strings.commonSuffix("", "abc"));
    assertEquals("", Strings.commonSuffix("abcde", "xyz"));
    assertEquals("", Strings.commonSuffix("xyz", "abcde"));
    assertEquals("", Strings.commonSuffix("xyz", "xyzabc"));
    assertEquals("c", Strings.commonSuffix("abc", "ccccc"));

   * b.toString().endsWith(suffix)}, taking care not to split surrogate pairs. If {@code a} and
   * {@code b} have no common suffix, returns the empty string.
   *
   * @since 11.0
   */
  public static String commonSuffix(CharSequence a, CharSequence b) {
    checkNotNull(a);
    checkNotNull(b);

    int maxSuffixLength = min(a.length(), b.length());
    int s = 0;