}

  public void test_contains_nonnull_iterable_no() {
    Iterable<String> set = iterable("a", "b");
    assertFalse(Iterables.contains(set, "c"));
  }

  public void testGetOnlyElement_noDefault_valid() {
    Iterable<String> iterable = singletonList("foo");
    assertThat(getOnlyElement(iterable)).isEqualTo("foo");
  }

  public void testGetOnlyElement_noDefault_empty() {