IllegalArgumentException.class, () -> networkAsMutableNetwork.addEdge(N4, N5, E12));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
    e = assertThrows(IllegalArgumentException.class, () -> addEdge(N2, N1, E12));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
  }

  @Test
  public void addEdge_parallelEdge_notAllowed() {
    assume().that(graphIsMutable()).isTrue();

 * buckets for the key and the value. This allows reuse in {@link RegularImmutableMap} and {@link
 * RegularImmutableBiMap}, which don't have to recopy the entries created by their {@code Builder}
 * implementations.
 *
 * <p>This base implementation has no key or value pointers, so instances of ImmutableMapEntry (but
 * not its subclasses) can be reused when copied from one ImmutableMap to another.
 *
 * @author Louis Wasserman

    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
    e =
        assertThrows(
            IllegalArgumentException.class, () -> networkAsMutableNetwork.addEdge(N2, N2, E11));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
    addEdge(N1, N2, E12);
    e =
        assertThrows(

      return new ByteArrayInputStream(memory.getBuffer(), 0, memory.getCount());
    }
  }

  /**
   * Calls {@link #close} if not already closed, and then resets this object back to its initial
   * state, for reuse. If data was buffered to a file, it will be deleted.
   *
   * @throws IOException if an I/O error occurred while deleting the file buffer
   */
  public synchronized void reset() throws IOException {
    try {

      InternetDomainName domain = InternetDomainName.from(inputName);

      /*
       * We would ordinarily use constants for the expected results, but
       * doing it by derivation allows us to reuse the test case definitions
       * used in other tests.
       */

      String expectedName = Ascii.toLowerCase(inputName);
      expectedName = expectedName.replaceAll("[\u3002\uFF0E\uFF61]", ".");

      } else {
        Helpers.assertEqualIgnoringOrder(expectedElements, targetElements);
      }
    }
  }

  private void recurse(int level) {
    // We're going to reuse the stimuli array 3^steps times by overwriting it
    // in a recursive loop.  Sneaky.
    if (level == stimuli.length) {
      // We've filled the array.
      compareResultsForThisListOfStimuli();
    } else {

      return Maps.keyIterator(entrySet().iterator());
    }
  }

  @LazyInit @CheckForNull private transient Set<V> valueSet;

  @Override
  public Set<V> values() {
    /*
     * We can almost reuse the inverse's keySet, except we have to fix the
     * iteration order so that it is consistent with the forward map.
     */
    Set<V> result = valueSet;
    return (result == null) ? valueSet = new ValueSet() : result;

      return Maps.keyIterator(entrySet().iterator());
    }
  }

  @LazyInit @CheckForNull private transient Set<V> valueSet;

  @Override
  public Set<V> values() {
    /*
     * We can almost reuse the inverse's keySet, except we have to fix the
     * iteration order so that it is consistent with the forward map.
     */
    Set<V> result = valueSet;
    return (result == null) ? valueSet = new ValueSet() : result;

            IllegalArgumentException.class, () -> networkAsMutableNetwork.addEdge(N4, N5, E12));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
    e = assertThrows(IllegalArgumentException.class, () -> addEdge(N2, N1, E12));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
  }

  @Test
  public void addEdge_parallelEdge_notAllowed() {
    assume().that(graphIsMutable()).isTrue();

      InternetDomainName domain = InternetDomainName.from(inputName);

      /*
       * We would ordinarily use constants for the expected results, but
       * doing it by derivation allows us to reuse the test case definitions
       * used in other tests.
       */

      String expectedName = Ascii.toLowerCase(inputName);
      expectedName = expectedName.replaceAll("[\u3002\uFF0E\uFF61]", ".");