.testSerializable();
  }

  public void testOfInstance_equals() {
    new EqualsTester()
        .addEqualityGroup(Suppliers.ofInstance("foo"), Suppliers.ofInstance("foo"))
        .addEqualityGroup(Suppliers.ofInstance("bar"))
        .testEquals();
  }

  public void testCompose_equals() {
    new EqualsTester()
        .addEqualityGroup(

import static java.util.Comparator.comparing;
import static java.util.Comparator.naturalOrder;
import static java.util.Comparator.reverseOrder;

import com.google.common.annotations.GwtCompatible;
import com.google.common.testing.EqualsTester;
import java.util.Collections;
import java.util.Comparator;
import java.util.Optional;
import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**

import java.util.ArrayList;
import java.util.List;
import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullMarked;

/**
 * Implementation helper for {@link EqualsTester} and {@link EquivalenceTester} that tests for
 * equivalence classes.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@NullMarked
final class RelationshipTester<T> {
  interface ItemReporter {

import com.google.common.collect.testing.TestStringSetGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.ForwardingWrapperTester;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.NavigableSet;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Iterators;
import com.google.common.collect.Maps;
import com.google.common.testing.EqualsTester;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;

    T instance = generator.newFreshProxy(interfaceType);
    new EqualsTester()
        .addEqualityGroup(wrapperFunction.apply(instance), wrapperFunction.apply(instance))
        .addEqualityGroup(wrapperFunction.apply(generator.newFreshProxy(interfaceType)))
        // TODO: add an overload to EqualsTester to print custom error message?
        .testEquals();
  }

  private static <T> void testToString(

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import java.util.Objects;
import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**

    new EqualsTester().addEqualityGroup(input, multimap).testEquals();
  }

  public void testCopyOfEmpty() {
    ArrayListMultimap<String, Integer> input = ArrayListMultimap.create();
    ImmutableListMultimap<String, Integer> multimap = ImmutableListMultimap.copyOf(input);
    new EqualsTester().addEqualityGroup(input, multimap).testEquals();
  }

    bf1.put("2");

    BloomFilter<String> bf2 = BloomFilter.create(Funnels.unencodedCharsFunnel(), 100);
    bf2.put("1");
    bf2.put("2");

    new EqualsTester().addEqualityGroup(bf1, bf2).testEquals();

    bf2.put("3");

    new EqualsTester().addEqualityGroup(bf1).addEqualityGroup(bf2).testEquals();
  }

  public void testEqualsWithCustomFunnel() {