Iterator<? extends E> elements);

  public void testCreation_noArgs() {
    Set<String> set = of();
    assertEquals(Collections.<String>emptySet(), set);
    assertSame(this.<String>of(), set);
  }

  public void testCreation_oneElement() {
    Set<String> set = of("a");
    assertEquals(Collections.singleton("a"), set);
  }

  public void testCreation_twoElements() {
    Set<String> set = of("a", "b");

    return ImmutableSet.copyOf(elements);
  }

  public void testCreation_allDuplicates() {
    ImmutableSet<String> set = ImmutableSet.copyOf(Lists.newArrayList("a", "a"));
    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 =

    return ImmutableSet.copyOf(elements);
  }

  public void testCreation_allDuplicates() {
    ImmutableSet<String> set = ImmutableSet.copyOf(Lists.newArrayList("a", "a"));
    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 =