public static StringSetData create(Set<String> set) {
    return new AutoValue_StringSetData(ImmutableSet.copyOf(set));
  }
@Test
  public void testCreate() {
    // test empty stringset creation
    assertTrue(StringSetData.create(Collections.emptySet()).stringSet().isEmpty());
    // single element test
    ImmutableSet<String> singleElement = ImmutableSet.of("ab");
    StringSetData setData = StringSetData.create(singleElement);
    assertEquals(setData.stringSet(), singleElement);

    // multiple element test
    ImmutableSet<String> multipleElement = ImmutableSet.of("cd", "ef");
    setData = StringSetData.create(multipleElement);
    assertEquals(setData.stringSet(), multipleElement);
  }