ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

 * identical to the original.
 *
 * @author Chris Povirk
 */
/*
 * The whole thing is really @GwtIncompatible, but GwtJUnitConvertedTestModule doesn't have a
 * parameter for non-GWT, non-test files, and it didn't seem worth adding one for this unusual case.
 */
@GwtCompatible(emulated = true)
final class LenientSerializableTester {
  /*
   * TODO(cpovirk): move this to c.g.c.testing if we allow for c.g.c.annotations dependencies so

 * identical to the original.
 *
 * @author Chris Povirk
 */
/*
 * The whole thing is really @GwtIncompatible, but GwtJUnitConvertedTestModule doesn't have a
 * parameter for non-GWT, non-test files, and it didn't seem worth adding one for this unusual case.
 */
@GwtCompatible(emulated = true)
final class LenientSerializableTester {
  /*
   * TODO(cpovirk): move this to c.g.c.testing if we allow for c.g.c.annotations dependencies so

    /*
     * In principle, a Multimap implementation could add e3 first before failing on the null. But
     * that seems unlikely enough to be worth complicating the test over, especially if there's any
     * chance that a permissive test could mask a bug.
     */
    expectUnchanged();
    // Be extra thorough in case internal state was corrupted by the expected null.

            obvious way to ensure that.

            We could consider arranging things so that only the tests we know need this would get
            the add-opens. Right now that doesn't seem worth the effort, though.
        -->
        <test.add.opens>
          --add-opens java.base/java.lang=ALL-UNNAMED
          --add-opens java.base/java.util=ALL-UNNAMED

            obvious way to ensure that.

            We could consider arranging things so that only the tests we know need this would get
            the add-opens. Right now that doesn't seem worth the effort, though.
        -->
        <test.add.opens>
          --add-opens java.base/java.lang=ALL-UNNAMED
          --add-opens java.base/java.util=ALL-UNNAMED

      super(forwardList);
    }
  }

  /** An implementation of {@link List#hashCode()}. */
  static int hashCodeImpl(List<?> list) {
    // TODO(lowasser): worth optimizing for RandomAccess?
    int hashCode = 1;
    for (Object o : list) {
      hashCode = 31 * hashCode + (o == null ? 0 : o.hashCode());

      hashCode = ~~hashCode;

  }

  /*
   * Now we have monster tests that create hundreds of Orderings using different
   * combinations of methods, then checks compare(), binarySearch() and so
   * forth on each one.
   */

  // should periodically try increasing this, but it makes the test run long
  private static final int RECURSE_DEPTH = 2;

  public void testCombinationsExhaustively_startingFromNatural() {

  }

  /*
   * Now we have monster tests that create hundreds of Orderings using different
   * combinations of methods, then checks compare(), binarySearch() and so
   * forth on each one.
   */

  // should periodically try increasing this, but it makes the test run long
  private static final int RECURSE_DEPTH = 2;

  public void testCombinationsExhaustively_startingFromNatural() {