public void testSortOrder() {
SortedMap map = makeTestSortedMap(oneFactory);
map.put("A", "a");
map.get("B"); // Entry with value "One" created
map.put("C", "c");
assertEquals("First key should be A", map.firstKey(), "A");
assertEquals("Last key should be C", map.lastKey(), "C");
assertEquals("First key in tail map should be B",
map.tailMap("B").firstKey(), "B");
assertEquals("Last key in head map should be B",
map.headMap("C").lastKey(), "B");