assertTrue(cycle.hasNext());
      assertEquals("b", cycle.next());
    }
  }

  public void testCycleOfTwoWithRemove() {
    Iterable<String> iterable = Lists.newArrayList("a", "b");
    Iterator<String> cycle = Iterators.cycle(iterable);
    assertTrue(cycle.hasNext());
    assertEquals("a", cycle.next());
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    assertTrue(cycle.hasNext());

      @Override
      public Iterator<T> iterator() {
        return Iterators.cycle(iterable);
      }

      @Override
      public String toString() {
        return iterable.toString() + " (cycled)";
      }
    };
  }

  /**
   * Returns an iterable whose iterators cycle indefinitely over the provided elements.
   *

    stimuli = (Stimulus<E, ? super I>[]) new Stimulus<?, ?>[steps];
    if (!elementsToInsertIterable.iterator().hasNext()) {
      throw new IllegalArgumentException();
    }
    elementsToInsert = Helpers.cycle(elementsToInsertIterable);
    this.features = Helpers.copyToSet(features);
    this.expectedElements = Helpers.copyToList(expectedElements);
    this.knownOrder = knownOrder;
    this.startIndex = startIndex;
  }

  // Graph query methods

  /**
   * Returns true if {@code graph} has at least one cycle. A cycle is defined as a non-empty subset
   * of edges in a graph arranged to form a path (a sequence of adjacent outgoing edges) starting
   * and ending with the same node.
   *
   * <p>This method will detect any non-empty cycle, including self-loops (a cycle of length 1).
   */
  public static <N> boolean hasCycle(Graph<N> graph) {

    stimuli = (Stimulus<E, ? super I>[]) new Stimulus<?, ?>[steps];
    if (!elementsToInsertIterable.iterator().hasNext()) {
      throw new IllegalArgumentException();
    }
    elementsToInsert = Helpers.cycle(elementsToInsertIterable);
    this.features = Helpers.copyToSet(features);
    this.expectedElements = Helpers.copyToList(expectedElements);
    this.knownOrder = knownOrder;
    this.startIndex = startIndex;
  }

   * should use an explicit {@code break} or be certain that you will eventually remove all the
   * elements.
   */
  @SafeVarargs
  public static <T extends @Nullable Object> Iterator<T> cycle(T... elements) {
    return cycle(Lists.newArrayList(elements));
  }

  /**
   * Returns an Iterator that walks the specified array, nulling out elements behind it. This can

  private void appendUserObject(StringBuilder builder, @CheckForNull Object o) {
    // This is some basic recursion detection for when people create cycles via set/setFuture or
    // when deep chains of futures exist resulting in a StackOverflowException. We could detect
    // arbitrary cycles using a thread local but this should be a good enough solution (it is also
    // what jdk collections do in these cases)
    try {