// identifiable substrings of expected error messages, from Strings that we've defined
  // here to provide error messages.
  // TODO(user): Some Strings used in the subclasses can be added as static Strings
  // here too.
  static final String ERROR_MODIFIABLE_SET = "Set returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";

   *
   * @param from the input stream to read from
   * @param to the output stream to write to
   * @return the number of bytes copied
   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue
  public static long copy(InputStream from, OutputStream to) throws IOException {
    checkNotNull(from);
    checkNotNull(to);
    byte[] buf = createBuffer();

   */
  public void tearDown() throws Exception {
    Throwable t = threadFailure.getAndSet(null);
    if (t != null) {
      if (t instanceof Error) throw (Error) t;
      else if (t instanceof RuntimeException) throw (RuntimeException) t;
      else if (t instanceof Exception) throw (Exception) t;
      else {

      throw new UncheckedExecutionException(e);
    } catch (Exception e) {
      statsCounter.recordLoadException(ticker.read() - startTime);
      throw new ExecutionException(e);
    } catch (Error e) {
      statsCounter.recordLoadException(ticker.read() - startTime);
      throw new ExecutionError(e);
    }

    if (calculatedValue == null) {

   *
   * <pre>{@code
   * Optional<Integer> optionalInt = getSomeOptionalInt();
   * Number value = optionalInt.or(0.5); // error
   *
   * FluentIterable<? extends Number> numbers = getSomeNumbers();
   * Optional<? extends Number> first = numbers.first();
   * Number value = first.or(0.5); // error
   * }</pre>
   *

              }
            }
          });
      try {
        future.get();
      } catch (Throwable t) {
        // Ignore, we just wanted to block.
      }
      String error = errorMessage.get();
      assertNull(error, error);
    }
    executor.shutdown();
  }

  /**
   * He did the bash, he did the future bash The future bash, it was a concurrency smash He did the

/** Utility methods used in various common.graph tests. */
final class TestUtil {
  static final String ERROR_ELEMENT_NOT_IN_GRAPH = "not an element of this graph";
  static final String ERROR_NODE_NOT_IN_GRAPH =
      "Should not be allowed to pass a node that is not an element of the graph.";
  static final String ERROR_ELEMENT_REMOVED = "used to generate this set";
  private static final String NODE_STRING = "Node";

/** Utility methods used in various common.graph tests. */
final class TestUtil {
  static final String ERROR_ELEMENT_NOT_IN_GRAPH = "not an element of this graph";
  static final String ERROR_NODE_NOT_IN_GRAPH =
      "Should not be allowed to pass a node that is not an element of the graph.";
  static final String ERROR_ELEMENT_REMOVED = "used to generate this set";
  private static final String NODE_STRING = "Node";

      throw new AssertionError();
    }
  }

  private static void wrapAndThrowUnchecked(Throwable cause) {
    if (cause instanceof Error) {
      throw new ExecutionError((Error) cause);
    }
    /*
     * It's an Exception. (Or it's a non-Error, non-Exception Throwable. From my survey of such
     * classes, I believe that most users intended to extend Exception, so we'll treat it like an
     * Exception.)

         */
        CombinedFuture.this.setException(((ExecutionException) error).getCause());
      } else if (error instanceof CancellationException) {
        cancel(false);
      } else {
        CombinedFuture.this.setException(error);
      }
    }

    abstract void setValue(@ParametricNullness T value);
  }

  @WeakOuter