public void testCdnStems() {
    AuState aus = new AuState(mau, historyRepo);
    assertEquals(Collections.EMPTY_LIST, aus.getCdnStems());
    aus.addCdnStem("http://fff.uselesstld");
    assertClass(ArrayList.class, aus.getCdnStems());
    assertEquals(ListUtil.list("http://fff.uselesstld"), aus.getCdnStems());
    aus.addCdnStem("ccc");
    assertEquals(ListUtil.list("http://fff.uselesstld", "ccc"), aus.getCdnStems());

    aus.setCdnStems(new LinkedList(ListUtil.list("a", "b")));
    assertClass(ArrayList.class, aus.getCdnStems());
    assertEquals(ListUtil.list("a", "b"), aus.getCdnStems());
    aus.setCdnStems(null);
    assertEmpty(aus.getCdnStems());
    aus.addCdnStem("https://a.b/");
    aus.addCdnStem("https://b.a/");
    assertEquals(ListUtil.list("https://a.b/", "https://b.a/"), aus.getCdnStems());
  }