@Test
public void test_insertionWorks() {

  Map<String, Integer> testMap = new ReferenceCountedHashMap<>();
  testMap.put(KEYS[0], VALUES[0]);
  Assert.assertEquals(testMap.get(KEYS[0]), VALUES[0]);
  testMap.put(KEYS[1], VALUES[1]);
  Assert.assertEquals(testMap.get(KEYS[0]), VALUES[0]);
  Assert.assertEquals(testMap.get(KEYS[1]), VALUES[1]);
  Assert.assertEquals(testMap.size(), 2);
}