static <K, V> void verify(Map<K, V> map, K k1, V v1, K k2, V v2)
    {
        map.put(k1, v1);
        map.put(k2, v2);

        Iterator<Map.Entry<K, V>> iter = map.entrySet().iterator();

        assertTrue(iter.hasNext());
        Map.Entry<K, V> first = iter.next();

        assertTrue(iter.hasNext());
        Map.Entry<K, V> second = iter.next();

        if (first == second)
        {
            // either IdentityHashMap or EnumMap
            System.err.println(map.getClass().getName() + " with entry: " + first.getClass().getName());
        }
    }
Test for Map impls that returns non-unique entries across iterator calls.

@author David Yu
@created Oct 22, 2011
protostuff-collectionschema/src/test/java/io/protostuff/UniqueMapEntryTest.java