assertThat(copy).isNotSameInstanceAs(sortedSet);
  }

  // TODO(b/172823566): Use mainline testToImmutableSet once CollectorTester is usable to java7.
  public void testToImmutableSet_java7() {
    ImmutableSet.Builder<String> zis = ImmutableSet.<String>builder().add("a", "b", "a");
    ImmutableSet.Builder<String> zat = ImmutableSet.<String>builder().add("c", "b", "d", "c");