public void testRemove_nullPresent() {
    collection = getSubjectGenerator().create(createArrayWithNullElement());

    int initialSize = collection.size();
    assertTrue("remove(null) should return true", collection.remove(null));
    assertEquals(
        "remove(present) should decrease a collection's size by one.",
        initialSize - 1,
        collection.size());
    expectMissing((E) null);
  }

import static java.util.Collections.emptyList;
import static java.util.Collections.singletonList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multimap;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.junit.Ignore;

  public void testRetainAll_duplicatesKept() {
    E[] array = createSamplesArray();
    array[1] = e0();
    collection = getSubjectGenerator().create(array);
    assertFalse(
        "containsDuplicates.retainAll(superset) should return false",
        collection.retainAll(MinimalCollection.of(createSamplesArray())));
    expectContents(array);
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

 *
 * <ul>
 *   <li><b>Shallow immutability.</b> Elements can never be added, removed or replaced in this
 *       collection. This is a stronger guarantee than that of {@link
 *       Collections#unmodifiableCollection}, whose contents change whenever the wrapped collection
 *       is modified.
 *   <li><b>Null-hostility.</b> This collection will never contain a null element.

   * elements than the collection), the element in the array immediately following the end of the
   * collection is set to {@code null}. This is useful in determining the length of the collection
   * <i>only</i> if the caller knows that the collection does not contain any null elements.
   *
   * <p>This method returns the elements in the order they are returned by the collection's
   * iterator.
   *

    while (entryIterator.hasNext()) {
      Entry<K, Collection<V>> entry = entryIterator.next();
      K key = entry.getKey();
      Collection<V> collection = filterCollection(entry.getValue(), new ValuePredicate(key));
      if (!collection.isEmpty()
          && predicate.apply(Maps.<K, Collection<V>>immutableEntry(key, collection))) {
        if (collection.size() == entry.getValue().size()) {
          entryIterator.remove();
        } else {

import com.google.common.collect.testing.features.Feature;
import com.google.common.collect.testing.testers.NavigableSetNavigationTester;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.NavigableSet;
import java.util.Set;
import java.util.SortedSet;
import junit.framework.TestSuite;

/**

  /**
   * Returns an iterable whose iterator returns the given elements in order. The elements are copied
   * out of the source collection at the time this method is called.
   */
  @SuppressWarnings("unchecked") // Es come in, Es go out
  public static <E extends @Nullable Object> MinimalIterable<E> from(Collection<E> elements) {
    return (MinimalIterable) of(elements.toArray());
  }

  private @Nullable Iterator<E> iterator;

    public Builder<E> addAll(Iterable<? extends E> elements) {
      if (elements instanceof Collection) {
        Collection<?> collection = (Collection<?>) elements;
        ensureRoomFor(collection.size());
        if (collection instanceof ImmutableCollection) {
          ImmutableCollection<?> immutableCollection = (ImmutableCollection<?>) collection;
          size = immutableCollection.copyIntoArray(contents, size);
          return this;

   */
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {
      Collection<?> collection1 = (Collection<?>) iterable1;
      Collection<?> collection2 = (Collection<?>) iterable2;
      if (collection1.size() != collection2.size()) {
        return false;
      }
    }