@Test
public void testValues() {

    IndexImpl<Node> index = generateEmptyIndex();
    NodeImpl[] nodes = generateNodesWithUniqueAttributes(index, true);
    putAll(nodes, index);
    for (Column col : index.columnStore) {
        if (col.isIndexed()) {
            Collection collection = index.values(col);
            ObjectSet<Object> expected = new ObjectOpenHashSet<Object>();
            for (NodeImpl n : nodes) {
                Object obj = n.getAttribute(col);
                expected.add(obj);
            }
            Assert.assertEquals(collection.size(), expected.size());
            Assert.assertEquals(index.countValues(col), expected.size());
            Assert.assertEquals(new ObjectOpenHashSet<Object>(collection), expected);
        }
    }
}