public void testValues() {
    dc.put("k1", "v1", 6000000, -1);
    dc.put("k2", "v2", -1, -1);
    dc.put("k3", "v3", -1, 6000000);
    dc.put("k4", "v4", 6000000, 6000000);

    Set expected = new HashSet();
    expected.add("v1");
    expected.add("v2");
    expected.add("v3");
    expected.add("v4");

    for (Object o : dc.values()) assert expected.remove(o);

    assert expected.isEmpty() : "Did not see keys " + expected + " in iterator!";
  }