@Override
                  protected Set<String> create(String[] elements) {
                    Set<String> set = newHashSet(elements);
                    Set<String> other = newHashSet("wz", "xq");
                    set.addAll(other);
                    other.add("pq");
                    return Sets.difference(set, other);
                  }
                })
            .named("set - set")

                  @Override
                  protected Set<String> create(String[] elements) {
                    Set<String> set = newHashSet(elements);
                    Set<String> other = newHashSet("wz", "xq");
                    set.addAll(other);
                    other.add("pq");
                    return Sets.difference(set, other);
                  }
                })
            .named("set - set")

1F12D         ; mapped                 ; 0063 0064     # 5.2  CIRCLED CD
1F12E         ; mapped                 ; 0077 007A     # 5.2  CIRCLED WZ
1F12F         ; valid                  ;      ; NV8    # 11.0 COPYLEFT SYMBOL
1F130         ; mapped                 ; 0061          # 6.0  SQUARED LATIN CAPITAL LETTER A