@Test
	public void testAsMapHeadLast() {
		populateStore(-3, -1, 1, 3);

		assertEquals(-1, doTestMap(map.headMap(0L, true), NavigableMap::lastKey, //
			NavigableMap::lastEntry).longValue());
		assertEquals(-1, doTestMap(map.headMap(-1L, true), NavigableMap::lastKey, //
			NavigableMap::lastEntry).longValue());
		assertEquals(-3, doTestMap(map.headMap(-1L, false), NavigableMap::lastKey, //
			NavigableMap::lastEntry).longValue());
		assertNull(doTestMap(map.headMap(-4L, true), NavigableMap::lastKey, //
			NavigableMap::lastEntry));

		assertEquals(1, doTestMap(rMap.headMap(0L, true), NavigableMap::lastKey, //
			NavigableMap::lastEntry).longValue());
		assertEquals(1, doTestMap(rMap.headMap(1L, true), NavigableMap::lastKey, //
			NavigableMap::lastEntry).longValue());
		assertEquals(3, doTestMap(rMap.headMap(1L, false), NavigableMap::lastKey, //
			NavigableMap::lastEntry).longValue());
		assertNull(doTestMap(rMap.headMap(4L, true), NavigableMap::lastKey, //
			NavigableMap::lastEntry));
	}
This exists to verify behavior in {@link #testAsValuesSubIterator()}
Ghidra/Debug/ProposedUtils/src/test/java/ghidra/util/database/DBCachedObjectStoreTest.java