CollectorTester<T, A, R> of(
          Collector<T, A, R> collector, BiPredicate<? super R, ? super R> equivalence) {
    return new CollectorTester<>(collector, equivalence);
  }

  private final Collector<T, A, R> collector;
  private final BiPredicate<? super R, ? super R> equivalence;

  private CollectorTester(

   * Collector} will be compared to the expected value using the specified {@code equivalence}.
   */
  public static <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>
      CollectorTester<T, A, R> of(
          Collector<T, A, R> collector, BiPredicate<? super R, ? super R> equivalence) {

import com.google.common.base.Equivalence;
import com.google.common.base.Function;
import com.google.common.base.MoreObjects;
import com.google.common.collect.Table.Cell;
import com.google.common.testing.CollectorTester;
import java.util.function.BiPredicate;
import java.util.function.BinaryOperator;
import java.util.stream.Collector;
import java.util.stream.Stream;
import junit.framework.TestCase;

    TypeWithDuplicates c = new TypeWithDuplicates(3, 1);
    CollectorTester.of(collector, equivalence)
        .expectCollects(
            ImmutableMultiset.<TypeWithDuplicates>builder().add(a).addCopies(b1, 2).add(c).build(),
            a,
            b1,
            c,
            b2);
    collector = toImmutableMultiset(e -> e, e -> 1);
    CollectorTester.of(collector, equivalence)
        .expectCollects(

import com.google.common.collect.testing.MapTestSuiteBuilder;
import com.google.common.collect.testing.TestEnumMapGenerator;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.testing.CollectorTester;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.Collector;
import java.util.stream.Stream;
import junit.framework.Test;
import junit.framework.TestCase;

import com.google.common.collect.testing.google.SetGenerators.ImmutableSetUnsizedBuilderGenerator;
import com.google.common.collect.testing.google.SetGenerators.ImmutableSetWithBadHashesGenerator;
import com.google.common.testing.CollectorTester;
import com.google.common.testing.EqualsTester;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import java.util.function.BiPredicate;

import com.google.common.collect.testing.google.SortedMapGenerators.ImmutableSortedMapValueListGenerator;
import com.google.common.testing.CollectorTester;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;

import com.google.common.collect.testing.google.SetGenerators.ImmutableSortedSetUnhashableGenerator;
import com.google.common.collect.testing.testers.SetHashCodeTester;
import com.google.common.testing.CollectorTester;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;

import com.google.common.collect.testing.google.TestStringSetMultimapGenerator;
import com.google.common.collect.testing.google.UnmodifiableCollectionTests;
import com.google.common.testing.CollectorTester;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import java.util.Arrays;
import java.util.Collection;

        assertThrows(IllegalArgumentException.class, () -> ImmutableBiMap.copyOf(map));
    assertThat(expected).hasMessageThat().containsMatch("1|2");
  }

  // TODO(b/172823566): Use mainline testToImmutableBiMap once CollectorTester is usable to java7.
  public void testToImmutableBiMap_java7_combine() {
    ImmutableBiMap.Builder<String, Integer> zis =
        ImmutableBiMap.<String, Integer>builder().put("one", 1);