* .
     */
    @Test
    public void testIsNotEmptyCollectionOfQ() {
        final Collection<String> c = new ArrayList<String>();
        c.add("hoge");
        assertThat(CollectionsUtil.isNotEmpty(c), is(true));
    }

    /**
     * Test method for
     * {@link org.codelibs.core.collection.CollectionsUtil#isEmpty(java.util.Map)}
     * .
     */

        if (entry.getKey().equals(key)) {
          expectedValues.add(entry.getValue());
        }
      }

      Collection<V> collection = multimap().asMap().get(key);
      if (expectedValues.isEmpty()) {
        assertNull(collection);
      } else {
        assertEqualIgnoringOrder(expectedValues, collection);
      }
    }
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)

    for (Collection<V> collection : asMap().values()) {
      if (collection.contains(value)) {
        return true;
      }
    }

    return false;
  }

  @Override
  public boolean containsEntry(@Nullable Object key, @Nullable Object value) {
    Collection<V> collection = asMap().get(key);
    return collection != null && collection.contains(value);
  }

  @CanIgnoreReturnValue

   * @return an array containing the same values as {@code collection}, in the same order, converted
   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   */
  public static boolean[] toArray(Collection<Boolean> collection) {
    if (collection instanceof BooleanArrayAsList) {
      return ((BooleanArrayAsList) collection).toBooleanArray();
    }

   * @return an array containing the same values as {@code collection}, in the same order, converted
   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   */
  public static boolean[] toArray(Collection<Boolean> collection) {
    if (collection instanceof BooleanArrayAsList) {
      return ((BooleanArrayAsList) collection).toBooleanArray();
    }

    final OneSizeTestContainerGenerator<Collection<E>, E> gen;

    private ReserializedCollectionGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override
    public Collection<E> create(Object... elements) {

        }
    }

    private ChannelInfo selectRoundRobin(Collection<ChannelInfo> channels) {
        List<ChannelInfo> list = new ArrayList<>(channels);
        int index = Math.abs(roundRobinCounter.getAndIncrement() % list.size());
        return list.get(index);
    }

    private ChannelInfo selectLeastLoaded(Collection<ChannelInfo> channels) {
        ChannelInfo leastLoadedChannel = null;

  }

  @Override
  public boolean add(E element) {
    return delegate.add(checkValid(element));
  }

  @Override
  public boolean addAll(Collection<? extends E> collection) {
    for (E e : collection) {
      checkValid(e);
    }
    return delegate.addAll(collection);
  }

  @Override
  public @Nullable E ceiling(E e) {
    return delegate.ceiling(checkValid(e));
  }

  @Override
  public void clear() {

      Entry<?, ?> entry = (Entry<?, ?>) element;
      element = mapEntry(entry.getKey(), entry.getValue());
    }
    assertTrue(collection.contains(element)); // sanity check
    iterator.remove();
    assertFalse(collection.contains(element));
    assertEquals(originalSize - 1, collection.size());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
  public void testIterator_knownOrderRemoveSupported() {

    Collection<V> result = multimap().asMap().get(k0());
    assertTrue(result.remove(v0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertEquals(2, multimap().size());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testPropagatesRemoveLastElementToMultimap() {
    Collection<V> result = multimap().asMap().get(k0());