assertEquals("one", copy.inverse().get(1));
    assertSame(copy, copy.inverse().inverse());
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testInverseSerialization() {
    ImmutableBiMap<String, Integer> bimap =
        ImmutableBiMap.copyOf(ImmutableMap.of(1, "one", 2, "two")).inverse();

    assertFalse(getMap().containsKey(k0()));

    assertTrue(getMap().containsKey(k1()));
    assertTrue(getMap().inverse().containsKey(null));
    assertNull(getMap().get(k1()));
    assertEquals(k1(), getMap().inverse().get(null));
    assertEquals(1, getMap().size());
  }

  // nb: inverse is run through its own entire suite

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(ZERO)

      Entry<V, K> reversed = reverseEntry(entry);
      BiMap<V, K> inv = getMap().inverse();
      assertFalse(
          "Inverse should not contain entry " + reversed, inv.entrySet().contains(reversed));
      assertFalse(
          "Inverse should not contain key " + reversed.getKey(),
          inv.containsKey(reversed.getKey()));
      assertFalse(
          "Inverse should not contain value " + reversed.getValue(),

      Entry<V, K> reversed = reverseEntry(entry);
      BiMap<V, K> inv = getMap().inverse();
      assertFalse(
          "Inverse should not contain entry " + reversed, inv.entrySet().contains(reversed));
      assertFalse(
          "Inverse should not contain key " + reversed.getKey(),
          inv.containsKey(reversed.getKey()));
      assertFalse(
          "Inverse should not contain value " + reversed.getValue(),

    }
    ImmutableMap<V, K> backwardMap = builder.build();
    this.inverse = new RegularImmutableBiMap<V, K>(backwardMap, this);
  }

  RegularImmutableBiMap(ImmutableMap<K, V> delegate, ImmutableBiMap<V, K> inverse) {
    super(delegate);
    this.inverse = inverse;
  }

  @Override
  public ImmutableBiMap<V, K> inverse() {
    return inverse;
  }

    if (!parentBuilder.getFeatures().contains(NoRecurse.INVERSE)) {
      derived.add(
          BiMapTestSuiteBuilder.using(
                  new InverseBiMapGenerator<K, V>(parentBuilder.getSubjectGenerator()))
              .withFeatures(computeInverseFeatures(parentBuilder.getFeatures()))
              .named(parentBuilder.getName() + " inverse")
              .suppressing(parentBuilder.getSuppressedTests())

    assertFalse(getMap().containsKey(k0()));

    assertTrue(getMap().containsKey(k1()));
    assertTrue(getMap().inverse().containsKey(null));
    assertNull(getMap().get(k1()));
    assertEquals(k1(), getMap().inverse().get(null));
    assertEquals(1, getMap().size());
  }

  // nb: inverse is run through its own entire suite

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(ZERO)

        ImmutableListMultimap.<String, Integer>of().inverse());
    assertEquals(ImmutableListMultimap.of(1, "one"), ImmutableListMultimap.of("one", 1).inverse());
    assertEquals(
        ImmutableListMultimap.of(1, "one", 2, "two"),
        ImmutableListMultimap.of("one", 1, "two", 2).inverse());
    assertEquals(
        ImmutableListMultimap.of("of", 'o', "of", 'f', "to", 't', "to", 'o').inverse(),

    assertEquals("one", copy.inverse().get(1));
    assertSame(copy, copy.inverse().inverse());
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testInverseSerialization() {
    ImmutableBiMap<String, Integer> bimap =
        ImmutableBiMap.copyOf(ImmutableMap.of(1, "one", 2, "two")).inverse();

    assertEquals("dollar", bimap.get("canada"));
    assertEquals("canada", bimap.inverse().get("dollar"));
  }

  private static final int N = 1000;

  public void testBashIt() throws Exception {
    BiMap<Integer, Integer> bimap = HashBiMap.create(N);
    BiMap<Integer, Integer> inverse = bimap.inverse();

    for (int i = 0; i < N; i++) {
      assertNull(bimap.put(2 * i, 2 * i + 1));
    }