public void testToSortedSet_removeDuplicates() {
    assertThat(fluent(1, 4, 1, 3).toSortedSet(Ordering.<Integer>natural().reverse()))
        .containsExactly(4, 3, 1)
        .inOrder();
  }

  public void testToMultiset() {
    assertThat(fluent(1, 2, 1, 3, 2, 4).toMultiset()).containsExactly(1, 1, 2, 2, 3, 4).inOrder();
  }

  public void testToMultiset_empty() {
    assertThat(fluent().toMultiset()).isEmpty();
  }