private static final class TestObject {
    final int group;
    final int item;

    TestObject(int group, int item) {
      this.group = group;
      this.item = item;
    }

    @Override
    public String toString() {
      return MoreObjects.toStringHelper("TestObject")
          .add("group", group)
          .add("item", item)
          .toString();
    }
  }

  private static final class TestObject {
    final int group;
    final int item;

    TestObject(int group, int item) {
      this.group = group;
      this.item = item;
    }

    @Override
    public String toString() {
      return MoreObjects.toStringHelper("TestObject")
          .add("group", group)
          .add("item", item)
          .toString();
    }
  }

    groups.add(ImmutableList.copyOf(group));
    return this;
  }

  public void test() {
    for (int groupNumber = 0; groupNumber < groups.size(); groupNumber++) {
      ImmutableList<T> group = groups.get(groupNumber);
      for (int itemNumber = 0; itemNumber < group.size(); itemNumber++) {
        // check related items in same group

    try {
      tester.testEquals();
    } catch (AssertionFailedError e) {
      assertErrorMessage(e, "foo [group 1, item 1] must be Object#equals to bar [group 1, item 2]");
      return;
    }
    fail("should failed because of unequal objects in the same equality group");
  }

  public void testTransitivityBrokenAcrossEqualityGroups() {
    EqualsTester tester =
        new EqualsTester()

  /**
   * Returns the {@link Executor} that will be used to run this service. Subclasses may override
   * this method to use a custom {@link Executor}, which may configure its worker thread with a
   * specific name, thread group or priority. The returned executor's {@link
   * Executor#execute(Runnable) execute()} method is called when this service is started and
   * stopped, and should return promptly.
   */
  protected Executor executor() {

import java.util.List;

/**
 * Tester for {@link Equivalence} relationships between groups of objects.
 *
 * <p>To use, create a new {@link EquivalenceTester} and add equivalence groups where each group
 * contains objects that are supposed to be equal to each other. Objects of different groups are
 * expected to be unequal. For example:
 *
 * <pre>{@code
 * EquivalenceTester.of(someStringEquivalence)

 *       groups and the items within equality groups are numbered starting from 1. When either a
 *       constructor argument or an equal object is provided, that becomes group 1.
 * </ul>
 *
 * @author Jim McMaster
 * @author Jige Yu
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class EqualsTester {

  /**
   * Returns the {@link Executor} that will be used to run this service. Subclasses may override
   * this method to use a custom {@link Executor}, which may configure its worker thread with a
   * specific name, thread group or priority. The returned executor's {@link
   * Executor#execute(Runnable) execute()} method is called when this service is started, and should
   * return promptly.
   *

 *       groups and the items within equality groups are numbered starting from 1. When either a
 *       constructor argument or an equal object is provided, that becomes group 1.
 * </ul>
 *
 * @author Jim McMaster
 * @author Jige Yu
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class EqualsTester {

import java.util.List;

/**
 * Tester for {@link Equivalence} relationships between groups of objects.
 *
 * <p>To use, create a new {@link EquivalenceTester} and add equivalence groups where each group
 * contains objects that are supposed to be equal to each other. Objects of different groups are
 * expected to be unequal. For example:
 *
 * <pre>{@code
 * EquivalenceTester.of(someStringEquivalence)