assertEquals(Country.class, bimap.valueType());
  }

  public void testIterationOrder() {
    // The enum orderings are alphabetical, leading to the bimap and its inverse
    // having inconsistent iteration orderings.
    Map<Currency, Country> map =
        ImmutableMap.of(
            Currency.DOLLAR, Country.CANADA,
            Currency.PESO, Country.CHILE,

      return putAll(key, asList(values));
    }

    /**
     * Stores another multimap's entries in the built multimap. The generated multimap's key and
     * value orderings correspond to the iteration ordering of the {@code multimap.asMap()} view,
     * with new keys and values following any existing keys and values.
     *

    testComparator(arbitrary, list);
  }

  public void testUsingToString() {
    Ordering<Object> ordering = Ordering.usingToString();
    testComparator(ordering, 1, 12, 124, 2);
    assertThat(ordering.toString()).isEqualTo("Ordering.usingToString()");
    assertThat(reserialize(ordering)).isSameInstanceAs(ordering);
  }

  // use an enum to get easy serializability

    testComparator(arbitrary, list);
  }

  public void testUsingToString() {
    Ordering<Object> ordering = Ordering.usingToString();
    testComparator(ordering, 1, 12, 124, 2);
    assertThat(ordering.toString()).isEqualTo("Ordering.usingToString()");
    assertThat(reserialize(ordering)).isSameInstanceAs(ordering);
  }

  // use an enum to get easy serializability

    Ordering<@Nullable Comparable<?>> result = nullsLast;
    if (result == null) {
      result = nullsLast = super.<Comparable<?>>nullsLast();
    }
    return (Ordering<@Nullable S>) result;
  }

  @Override
  @SuppressWarnings("unchecked") // TODO(kevinb): the right way to explain this??
  public <S extends Comparable<?>> Ordering<S> reverse() {

    Ordering<@Nullable Comparable<?>> result = nullsLast;
    if (result == null) {
      result = nullsLast = super.<Comparable<?>>nullsLast();
    }
    return (Ordering<@Nullable S>) result;
  }

  @Override
  @SuppressWarnings("unchecked") // TODO(kevinb): the right way to explain this??
  public <S extends Comparable<?>> Ordering<S> reverse() {

    assertEquals(tree, copyFromTree);
    assertThat(copyFromTree.keyComparator()).isEqualTo(Ordering.natural());
    assertThat(copyFromTree.valueComparator()).isEqualTo(Ordering.natural());
    assertThat(copyFromTree.get(1.0).comparator()).isEqualTo(Ordering.natural());
  }

  /** Test that creating one TreeMultimap from a non-TreeMultimap results in natural ordering. */
  public void testCreateFromHashMultimap() {

  /**
   * The type of ordering that this object specifies.
   *
   * <ul>
   *   <li>UNORDERED: no order is guaranteed.
   *   <li>STABLE: ordering is guaranteed to follow a pattern that won't change between releases.
   *       Some methods may have stronger guarantees.
   *   <li>INSERTION: insertion ordering is guaranteed.
   *   <li>SORTED: ordering according to a supplied comparator is guaranteed.
   * </ul>

    assertEquals(tree, copyFromTree);
    assertThat(copyFromTree.keyComparator()).isEqualTo(Ordering.natural());
    assertThat(copyFromTree.valueComparator()).isEqualTo(Ordering.natural());
    assertThat(copyFromTree.get(1.0).comparator()).isEqualTo(Ordering.natural());
  }

  /** Test that creating one TreeMultimap from a non-TreeMultimap results in natural ordering. */
  public void testCreateFromHashMultimap() {

  @WeakOuter
  private final class Heap {
    final Ordering<E> ordering;

    @SuppressWarnings("nullness:initialization.field.uninitialized")
    @Weak
    Heap otherHeap; // always initialized immediately after construction

    Heap(Ordering<E> ordering) {
      this.ordering = ordering;
    }

    int compareElements(int a, int b) {
      return ordering.compare(elementData(a), elementData(b));
    }