StringBuilder sb = new StringBuilder();
    j.appendTo(sb, ImmutableMap.of(1, 2, 3, 4, 5, 6));
    assertEquals("1:2;3:4;5:6", sb.toString());
  }

  public void testEntries() {
    MapJoiner j = Joiner.on(";").withKeyValueSeparator(":");
    assertEquals("", j.join(ImmutableMultimap.of().entries()));
    assertEquals("", j.join(ImmutableMultimap.of().entries().iterator()));