assertThat(map.entrySet())
        .containsExactly(mapEntry("one", 3), mapEntry("two", 3), mapEntry("three", 5))
        .inOrder();
  }

  public void testToMapWithNullKeys() {
    Iterable<@Nullable String> strings = asList("one", null, "three");
    assertThrows(
        NullPointerException.class,
        () -> Maps.toMap((Iterable<String>) strings, Functions.constant("foo")));