Iterable<String> iterable = asList("foo", "bar");
    assertThrows(IllegalArgumentException.class, () -> getOnlyElement(iterable, "x"));
  }

  @GwtIncompatible // Iterables.toArray(Iterable, Class)
  public void testToArrayEmpty() {
    Iterable<String> iterable = emptyList();
    String[] array = Iterables.toArray(iterable, String.class);
    assertThat(array).isEmpty();
  }

  @GwtIncompatible // Iterables.toArray(Iterable, Class)

    assertThat(expected).hasMessageThat().isEqualTo("expected one element but was: <foo, bar>");
  }

  @GwtIncompatible // Iterators.toArray(Iterator, Class)
  public void testToArrayEmpty() {
    Iterator<String> iterator = Collections.<String>emptyList().iterator();
    String[] array = Iterators.toArray(iterator, String.class);
    assertThat(array).isEmpty();
  }