new ImmutableMultiset.Builder<String>().addCopies("x", 10).build();
    multiset.addAll(adds);
    assertEquals(1, addCalls.get());
  }

  public void testRemoveUnsupported() {
    Multiset<String> multiset = new NoRemoveMultiset<>();
    multiset.add("a");
    assertThrows(UnsupportedOperationException.class, () -> multiset.remove("a"));
    assertTrue(multiset.contains("a"));
  }

        (multiset1, multiset2) -> {
          multiset1.addAll(multiset2);
          return multiset1;
        },
        (Multiset<E> multiset) -> ImmutableMultiset.copyFromEntries(multiset.entrySet()));
  }

  static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,

        (multiset1, multiset2) -> {
          multiset1.addAll(multiset2);
          return multiset1;
        },
        (Multiset<E> multiset) -> ImmutableMultiset.copyFromEntries(multiset.entrySet()));
  }

  static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,

  public void testEquals_yes() {
    assertTrue(
        "multiset doesn't equal a multiset with the same elements",
        getMultiset().equals(HashMultiset.create(getSampleElements())));
  }

  public void testEquals_differentSize() {
    Multiset<E> other = HashMultiset.create(getSampleElements());
    other.add(e0());
    assertFalse("multiset equals a multiset with a different size", getMultiset().equals(other));
  }

  public void testEquals_yes() {
    assertTrue(
        "multiset doesn't equal a multiset with the same elements",
        getMultiset().equals(HashMultiset.create(getSampleElements())));
  }

  public void testEquals_differentSize() {
    Multiset<E> other = HashMultiset.create(getSampleElements());
    other.add(e0());
    assertFalse("multiset equals a multiset with a different size", getMultiset().equals(other));
  }

  }

  @Generates
  static <E> Multiset<E> generateMultiset(@Nullable E freshElement) {
    return generateHashMultiset(freshElement);
  }

  @Generates
  static <E> HashMultiset<E> generateHashMultiset(@Nullable E freshElement) {
    HashMultiset<E> multiset = HashMultiset.create();
    multiset.add(freshElement);
    return multiset;
  }

  @Generates

import com.google.common.collect.testing.features.CollectionSize;
import java.lang.reflect.Method;
import java.util.List;
import org.junit.Ignore;

/**
 * Tests for {@code Multiset#remove}, {@code Multiset.removeAll}, and {@code Multiset.retainAll} not
 * already covered by the corresponding Collection testers.
 *
 * @author Jared Levy
 */
@GwtCompatible

import com.google.common.collect.testing.features.CollectionSize;
import java.lang.reflect.Method;
import java.util.List;
import org.junit.Ignore;

/**
 * Tests for {@code Multiset#remove}, {@code Multiset.removeAll}, and {@code Multiset.retainAll} not
 * already covered by the corresponding Collection testers.
 *
 * @author Jared Levy
 */
@GwtCompatible

  }

  public void testClassCreate() {
    Multiset<Color> ms = EnumMultiset.create(Color.class);
    ms.add(Color.RED);
    ms.add(Color.YELLOW);
    ms.add(Color.RED);
    assertEquals(0, ms.count(Color.BLUE));
    assertEquals(1, ms.count(Color.YELLOW));
    assertEquals(2, ms.count(Color.RED));
  }

  public void testCollectionCreate() {

/**
 * This class provides a skeletal implementation of the {@link SortedMultiset} interface.
 *
 * <p>The {@link #count} and {@link #size} implementations all iterate across the set returned by
 * {@link Multiset#entrySet()}, as do many methods acting on the set returned by {@link
 * #elementSet()}. Override those methods for better performance.
 *
 * @author Louis Wasserman
 */
@GwtCompatible