*   <li>{@code [2, 4)} and {@code [4, 6)} are connected, because both enclose the empty range
   *       {@code [4, 4)}
   * </ul>
   *
   * <p>Note that this range and {@code other} have a well-defined {@linkplain #span union} and
   * {@linkplain #intersection intersection} (as a single, possibly-empty range) if and only if this
   * method returns {@code true}.
   *

      assertTrue(set.containsAll(subset));
    }
    for (Set<Integer> subset : Sets.powerSet(ImmutableSet.of(1, 2, 3))) {
      assertFalse(set.containsAll(Sets.union(subset, ImmutableSet.of(9))));
    }
    assertFalse(set.containsAll((Collection<?>) ImmutableSet.of("blah")));
  }

  public void testRange() {

      assertTrue(set.containsAll(subset));
    }
    for (Set<Integer> subset : Sets.powerSet(ImmutableSet.of(1, 2, 3))) {
      assertFalse(set.containsAll(Sets.union(subset, ImmutableSet.of(9))));
    }
    assertFalse(set.containsAll((Collection<?>) ImmutableSet.of("blah")));
  }

  public void testRange() {

    }

    // Each of the values added to the map should either still be there, or have seen a removal
    // notification.
    assertEquals(expectedKeys, Sets.union(cache.asMap().keySet(), removalNotifications.keySet()));
    assertTrue(Sets.intersection(cache.asMap().keySet(), removalNotifications.keySet()).isEmpty());
  }

  /**