code: private static String formatDirName(final String prefix, final String suffix) {
          // Replace all invalid characters with '-'
          final CharMatcher invalidCharacters = VALID_SUFFIX_CHARS.negate();
          return String.format("%s-%s", prefix, invalidCharacters.trimAndCollapseFrom(suffix.toLowerCase(), '-'));
      }
docs: Returns the expected name of a workspace for a given suffix
  @param suffix
  @return