public void testFrequency_multiset() {
    Multiset<String> multiset = ImmutableMultiset.of("a", "b", "a", "c", "b", "a");
    assertEquals(3, frequency(multiset, "a"));
    assertEquals(2, frequency(multiset, "b"));
    assertEquals(1, frequency(multiset, "c"));
    assertEquals(0, frequency(multiset, "d"));
    assertEquals(0, frequency(multiset, 4.2));
    assertEquals(0, frequency(multiset, null));
  }

import static java.util.Collections.nCopies;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multiset.Entry;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link Multisets#immutableEntry}.
 *
 * @author Mike Bostock
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

    getMultiset().elementSet().clear();
    assertEmpty(getMultiset());
  }

  /**
   * Returns {@link Method} instances for the read tests that assume multisets support duplicates so
   * that the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getElementSetDuplicateInitializingMethods() {
    return asList(

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests conditional {@code setCount()} operations on a multiset. Can't
 * be invoked directly; please see {@link MultisetTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

 * return {@code SortedSet}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
interface SortedMultisetBridge<E extends @Nullable Object> extends Multiset<E> {
  @Override
  SortedSet<E> elementSet();

    getMultiset().elementSet().clear();
    assertEmpty(getMultiset());
  }

  /**
   * Returns {@link Method} instances for the read tests that assume multisets support duplicates so
   * that the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getElementSetDuplicateInitializingMethods() {
    return asList(

        return getSubjectGenerator().create(e0(), e1(), e1(), e2()).iterator();
      }
    }.test();
  }

  /**
   * Returns {@link Method} instances for the tests that assume multisets support duplicates so that
   * the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getIteratorDuplicateInitializingMethods() {
    return asList(

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests conditional {@code setCount()} operations on a multiset. Can't
 * be invoked directly; please see {@link MultisetTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

    // targets.size() < size() / log(size())
    // TODO(kevinb): see if we can share code with OrderedIterator after it
    // graduates from labs.
    if (targets instanceof Multiset) {
      targets = ((Multiset<?>) targets).elementSet();
    }
    if (!SortedIterables.hasSameComparator(comparator(), targets) || (targets.size() <= 1)) {
      return super.containsAll(targets);
    }

    /*

 *
 * <p><b>Note:</b> If your values are always positive and less than 2^31, you may wish to use a
 * {@link com.google.common.collect.Multiset} such as {@link
 * com.google.common.collect.ConcurrentHashMultiset} instead.
 *
 * <p><b>Warning:</b> Unlike {@code Multiset}, entries whose values are zero are not automatically
 * removed from the map. Instead they must be removed manually with {@link #removeAllZeros}.
 *