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(

    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(

    assertThat(set).containsExactly("a", "in", "the", "over", "quick", "jumped").inOrder();
    assertSame(STRING_LENGTH, set.comparator());
  }

  // TODO(b/172823566): Use mainline testToImmutableSortedSet once CollectorTester is usable.
  public void testToImmutableSortedSet_java7() {
    // Note that a Collector should generally enforce consistent comparator between builders
    ImmutableSortedSet.Builder<String> zis =

import com.google.common.collect.testing.google.TestStringListMultimapGenerator;
import com.google.common.collect.testing.google.UnmodifiableCollectionTests;
import com.google.common.primitives.Chars;
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;

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.ListGenerators.UnhashableElementsImmutableListGenerator;
import com.google.common.collect.testing.testers.ListHashCodeTester;
import com.google.common.testing.CollectorTester;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

    ImmutableSet<String> copy = ImmutableSet.copyOf(sortedSet);
    assertNotSame(sortedSet, copy);
  }

  // TODO(b/172823566): Use mainline testToImmutableSet once CollectorTester is usable to java7.
  public void testToImmutableSet_java7() {
    ImmutableSet.Builder<String> zis = ImmutableSet.<String>builder().add("a", "b", "a");

    assertMapEquals(copy, "one", 1, "two", 2, "three", 3);
    assertSame(copy, ImmutableMap.copyOf(copy));
  }

  // TODO(b/172823566): Use mainline testToImmutableMap once CollectorTester is usable to java7.
  public void testToImmutableMap_java7_combine() {
    ImmutableMap.Builder<String, Integer> zis =
        ImmutableMap.<String, Integer>builder().put("one", 1);

        NullPointerException.class,
        () -> ImmutableListMultimap.copyOf((ArrayListMultimap<String, Integer>) input));
  }

  // TODO(b/172823566): Use mainline testToImmutableListMultimap once CollectorTester is usable.
  public void testToImmutableListMultimap_java7_combine() {
    ImmutableListMultimap.Builder<String, Integer> zis =
        ImmutableListMultimap.<String, Integer>builder().put("a", 1).put("b", 2);

        NullPointerException.class,
        () -> ImmutableList.sortedCopyOf(String.CASE_INSENSITIVE_ORDER, (Collection<String>) c));
  }

  // TODO(b/172823566): Use mainline testToImmutableList once CollectorTester is usable to java7.
  public void testToImmutableList_java7_combine() {
    ImmutableList.Builder<String> zis = ImmutableList.<String>builder().add("a", "b");