public void testOrdering() {
Bag bag = setupBag();
assertEquals("Should get elements in correct order", "A", bag.toArray()[0]);
assertEquals("Should get elements in correct order", "B", bag.toArray()[1]);
assertEquals("Should get elements in correct order", "C", bag.toArray()[2]);
assertEquals("Should get first key", "A", ((SortedBag) bag).first());
assertEquals("Should get last key", "D", ((SortedBag) bag).last());
}
public String getCompatibilityVersion() {