protected Long doTestMap(NavigableMap<Long, MyObject> m,
			Function<NavigableMap<Long, MyObject>, Long> fK,
			Function<NavigableMap<Long, MyObject>, Entry<Long, MyObject>> fE) {
		Long k = fK.apply(m);
		Entry<Long, MyObject> ent = fE.apply(m);
		if (k == null) {
			assertNull(ent);
		}
		else {
			assertEquals(k, ent.getKey());
		}
		return k;
	}
This exists to verify behavior in {@link #testAsValuesSubIterator()}
Ghidra/Debug/ProposedUtils/src/test/java/ghidra/util/database/DBCachedObjectStoreTest.java