}
    assertFalse(errorNotThrown);
  }

  private static class ClassWhichDoesNotImplementEquals implements Serializable {
    private static final long serialVersionUID = 1L;
  }

  private static class ClassWhichIsAlwaysEqualButHasDifferentHashcodes implements Serializable {
    private static final long serialVersionUID = 2L;

    @SuppressWarnings("EqualsHashCode")
    @Override

    }
    assertFalse(errorNotThrown);
  }

  private static class ClassWhichDoesNotImplementEquals implements Serializable {
    private static final long serialVersionUID = 1L;
  }

  private static class ClassWhichIsAlwaysEqualButHasDifferentHashcodes implements Serializable {
    private static final long serialVersionUID = 2L;

    @SuppressWarnings("EqualsHashCode")
    @Override

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.Duration;
import java.util.Objects;
import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.Nullable;

/**
 * Useful suppliers.
 *
 * <p>All methods return serializable suppliers as long as they're given serializable parameters.
 *
 * @author Laurence Gonsalves
 * @author Harry Heymann
 * @since 2.0

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.Duration;
import java.util.Objects;
import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.Nullable;

/**
 * Useful suppliers.
 *
 * <p>All methods return serializable suppliers as long as they're given serializable parameters.
 *
 * @author Laurence Gonsalves
 * @author Harry Heymann
 * @since 2.0

import com.google.common.collect.testing.google.MultisetTestSuiteBuilder;
import com.google.common.collect.testing.google.TestStringMultisetGenerator;
import com.google.common.testing.SerializableTester;
import java.io.Serializable;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullMarked;

/**
 * Unit test for {@link HashMultiset}.
 *

            .named(ImmutableSetTest.class.getName())
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(new ImmutableSetUnsizedBuilderGenerator())

import static com.google.common.collect.Maps.immutableEntry;

import com.google.common.collect.testing.SampleElements;
import com.google.common.collect.testing.TestMapGenerator;
import java.io.Serializable;
import java.util.List;
import java.util.Map.Entry;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Unit test for {@link ImmutableClassToInstanceMap}.
 *

   * covered.
   */
  protected final void publicApiOnly() {
    visibility = Visibility.PUBLIC;
  }

  /**
   * Tests all top-level {@link Serializable} classes in the package. For a serializable Class
   * {@code C}:
   *
   * <ul>
   *   <li>If {@code C} explicitly implements {@link Object#equals}, the deserialized instance will

import com.google.common.collect.testing.google.MultisetTestSuiteBuilder;
import com.google.common.collect.testing.google.TestStringMultisetGenerator;
import com.google.common.testing.SerializableTester;
import java.io.Serializable;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullMarked;

/**
 * Unit test for {@link HashMultiset}.
 *

   * covered.
   */
  protected final void publicApiOnly() {
    visibility = Visibility.PUBLIC;
  }

  /**
   * Tests all top-level {@link Serializable} classes in the package. For a serializable Class
   * {@code C}:
   *
   * <ul>
   *   <li>If {@code C} explicitly implements {@link Object#equals}, the deserialized instance will