assertEquals(3, (int) mmHeap.peek());
    assertEquals(3, (int) mmHeap.poll());
    assertNull(mmHeap.peekLast());
    assertNull(mmHeap.peek());
    assertNull(mmHeap.poll());
  }

  public void testRemove() {
    MinMaxPriorityQueue<Integer> mmHeap = MinMaxPriorityQueue.create();
    mmHeap.addAll(Lists.newArrayList(1, 2, 3, 4, 47, 1, 5, 3, 0));
    assertTrue("Heap is not intact initially", mmHeap.isIntact());

    } else {
      assertThrows(UnsupportedOperationException.class, () -> map.putAll(mapToPut));
    }
    assertEquals(initialSize, map.size());
    assertInvariants(map);
  }

  public void testRemove() {
    Map<K, V> map;
    try {
      map = makePopulatedMap();
    } catch (UnsupportedOperationException e) {
      return;
    }
    K keyToRemove = map.keySet().iterator().next();

    File parent = getTestFile("ascii.txt");
    assertTrue(parent.isFile());
    File file = file(parent, "foo");
    assertThrows(IOException.class, () -> Files.createParentDirs(file));
  }

  public void testMove() throws IOException {
    File i18nFile = getTestFile("i18n.txt");
    File temp1 = createTempFile();
    File temp2 = createTempFile();

    Files.copy(i18nFile, temp1);
    moveHelper(true, temp1, temp2);

    File parent = getTestFile("ascii.txt");
    assertTrue(parent.isFile());
    File file = file(parent, "foo");
    assertThrows(IOException.class, () -> Files.createParentDirs(file));
  }

  public void testMove() throws IOException {
    File i18nFile = getTestFile("i18n.txt");
    File temp1 = createTempFile();
    File temp2 = createTempFile();

    Files.copy(i18nFile, temp1);
    moveHelper(true, temp1, temp2);