@Test
	public void testAsEntrySetSubFirst() {
		DBCachedObjectStoreEntrySubSet<MyObject> subSet =
			entrySet.subSet(ent(-2), true, ent(2), true);
		assertNull(subSet.first());
		populateStore(-3, -1, 1, 3);
		assertEquals(-1, subSet.first().getKey().longValue());
	}
This exists to verify behavior in {@link #testAsValuesSubIterator()}
Ghidra/Debug/ProposedUtils/src/test/java/ghidra/util/database/DBCachedObjectStoreTest.java