assertTrue(set instanceof SingletonImmutableSet);
    assertEquals(Lists.newArrayList("a"), Lists.newArrayList(set));
  }

  public void testCreation_oneDuplicate() {
    // now we'll get the varargs overload
    ImmutableSet<String> set =
        ImmutableSet.of("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "a");
    assertEquals(