@Test
	public void testAsKeySetSubHeadSet() {
		assertEquals(KeySpan.closed(-2L, 2L),
			keySet.subSet(-2L, true, 4L, false).headSet(2L, true).keySpan);
		assertEquals(KeySpan.closed(-2L, 2L),
			rKeySet.subSet(2L, true, -4L, false).headSet(-2L, true).keySpan);
	}
This exists to verify behavior in {@link #testAsValuesSubIterator()}
Ghidra/Debug/ProposedUtils/src/test/java/ghidra/util/database/DBCachedObjectStoreTest.java