@Test
    public void testAddAll() {
        final List<String> stuff = doubleAdd();
        final ArraySet<String> t = new ArraySet<>(
                stuff.size());
        t.addAll(stuff);
        assertEquals(stuff.size() / 2, t.size());
    }
Check ArraySet seems to work. :)

@author <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
vespajlib/src/test/java/com/yahoo/collections/ArraySetTestCase.java