public void EmptyReturnsEmpty()
{
Dictionary <int, string> d = new Dictionary <int, string>();
d[1] = "a";
d[2] = "b";
IPersistentMap m = PersistentArrayMap.create(d);
IPersistentCollection c = m.empty();
Expect(c.count(), EqualTo(0));
Expect(c.seq(), Null);
}