*   <li>keys automatically wrapped in {@code WeakReference}
 *   <li>values automatically wrapped in {@code WeakReference} or {@code SoftReference}
 *   <li>notification of evicted (or otherwise removed) entries
 *   <li>accumulation of cache access statistics
 * </ul>
 *
 * <p>These features are all optional; caches can be created using all or none of them. By default,

    the [Guava Beta Checker] to ensure that you do not use any `@Beta` APIs!**

2.  APIs without `@Beta` will remain binary-compatible for the indefinite
    future. (Previously, we sometimes removed such APIs after a deprecation
    period. The last release to remove non-`@Beta` APIs was Guava 21.0.) Even
    `@Deprecated` APIs will remain (again, unless they are `@Beta`). We have no
    plans to start removing things again, but officially, we're leaving our

        assertThat(network.removeNode(nodeList.get(i))).isTrue();
      }

      assertThat(network.nodes()).hasSize(NUM_NODES - numNodesToRemove);
      // Number of edges remaining is unknown (node's incident edges have been removed).
      AbstractNetworkTest.validateNetwork(network);

      for (int i = numNodesToRemove; i < NUM_NODES; ++i) {
        assertThat(network.removeNode(nodeList.get(i))).isTrue();
      }

    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertEdgeRemovedFromGraphErrorMessage(Throwable throwable) {
    assertThat(throwable).hasMessageThat().startsWith(EDGE_STRING);
    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertStronglyEquivalent(Graph<?> graphA, Graph<?> graphB) {

    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertEdgeRemovedFromGraphErrorMessage(Throwable throwable) {
    assertThat(throwable).hasMessageThat().startsWith(EDGE_STRING);
    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertStronglyEquivalent(Graph<?> graphA, Graph<?> graphB) {

   * this graph.
   *
   * <p>This is equal to the union of {@link #predecessors(Object)} and {@link #successors(Object)}.
   *
   * <p>If {@code node} is removed from the graph after this method is called, the {@code Set}
   * {@code view} returned by this method will be invalidated, and will throw {@code
   * IllegalStateException} if it is accessed in any way, with the following exceptions:

  public enum Modifiability {
    NONE, // immutable lists
    BY_ELEMENT, // elements can change (set), but not structure
    DIRECT_ONLY, // Element can be added and removed only via direct calls, not through iterators
    ALL // Elements can be added and removed as well as modified.
  }

  /** Handles the creation of lists needed for the tests */
  public abstract static class ListExample {

    private final String name;

      iterator.next();
      iterator.remove();
      assertEquals(initialSize - 1, map.size());
      // (We can't assert that the values collection no longer contains the
      // removed value, because the underlying map can have multiple mappings
      // to the same value.)
      assertInvariants(map);
      try {
        iterator.remove();
        fail("Expected IllegalStateException.");

    runConcurrentlyMutatedTest(elements(1), ops(remove(), add(2)), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(remove(), remove()), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(remove(), nop()), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(remove(), add(3)), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(nop(), remove()), wrap);

      }
    }
  }

  private void compareResultsForThisListOfStimuli() {
    int removes = Collections.frequency(Arrays.asList(stimuli), remove);
    if ((!features.contains(IteratorFeature.SUPPORTS_REMOVE) && removes > 1)
        || (stimuli.length >= 5 && removes > 2)) {
      // removes are the most expensive thing to test, since they often throw exceptions with stack