@Test public void concat_concatenates() {

  List<Object> list1 = ImmutableList.of("foo");
  List<Object> list2 = ImmutableList.of("bar", "baz");
  assertThat(Lists.concat(list1, list2))
    .hasSameClassAs(Collections.unmodifiableList(list1))
    .containsExactly("foo", "bar", "baz");
}