timings.add(endTime - startTime);
                        assertFalse(result, "Passwords should not be equal");
                    }
                });
            }

            executor.shutdown();
            assertTrue(executor.awaitTermination(30, TimeUnit.SECONDS), "All threads should complete within timeout");

            // Analyze timing consistency across threads
            if (!timings.isEmpty()) {

        break;
      }
    }
  }

  /** Waits out termination of a thread pool or fails doing so. */
  final void joinPool(ExecutorService exec) throws InterruptedException {
    try {
      exec.shutdown();
      assertTrue(
          "ExecutorService did not terminate in a timely manner",
          exec.awaitTermination(2 * LONG_DELAY_MS, MILLISECONDS));
    } catch (SecurityException ok) {

      barrier.await(1, SECONDS);
      executor.execute(barrierTask);
      // timeout means the second task wasn't even tried
      barrier.await(1, SECONDS);
    } finally {
      service.shutdown();
    }
  }

  public void testRejectedExecutionThrownWithMultipleCalls() throws Exception {
    CountDownLatch latch = new CountDownLatch(1);
    SettableFuture<?> future = SettableFuture.create();

      barrier.await(1, SECONDS);
      executor.execute(barrierTask);
      // timeout means the second task wasn't even tried
      barrier.await(1, SECONDS);
    } finally {
      service.shutdown();
    }
  }

  public void testRejectedExecutionThrownWithMultipleCalls() throws Exception {
    CountDownLatch latch = new CountDownLatch(1);
    SettableFuture<?> future = SettableFuture.create();

    assertThat(Sets.union(cache.asMap().keySet(), removalNotifications.keySet()))
        .isEqualTo(expectedKeys);
    assertThat(cache.asMap().keySet()).containsNoneIn(removalNotifications.keySet());
    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);
  }

  /**
   * Calls get() repeatedly from many different threads, and tests that all of the removed entries

    assertThat(Sets.union(cache.asMap().keySet(), removalNotifications.keySet()))
        .isEqualTo(expectedKeys);
    assertThat(cache.asMap().keySet()).containsNoneIn(removalNotifications.keySet());
    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);
  }

  /**
   * Calls get() repeatedly from many different threads, and tests that all of the removed entries

    }

    @Test
    public void test_shutdown() throws Exception {
        Suggester suggester = createSuggester();

        // Should not throw
        suggester.shutdown();
    }

        break;
      }
    }
  }

  /** Waits out termination of a thread pool or fails doing so. */
  final void joinPool(ExecutorService exec) throws InterruptedException {
    try {
      exec.shutdown();
      assertTrue(
          "ExecutorService did not terminate in a timely manner",
          exec.awaitTermination(2 * LONG_DELAY_MS, MILLISECONDS));
    } catch (SecurityException ok) {

  private ExecutorService threadPool;

  @Override
  public void setUp() {
    threadPool = newCachedThreadPool();
  }

  @Override
  public void tearDown() throws InterruptedException {
    threadPool.shutdown();
    assertTrue("Some worker didn't finish in time", threadPool.awaitTermination(10, SECONDS));
  }

  private static <T> int drain(
      BlockingQueue<T> q,
      Collection<? super T> buffer,

                }
            }));
        }

        startLatch.countDown();
        for (final Future<?> future : futures) {
            future.get();
        }

        executor.shutdown();
        assertEquals(0, errors.get());
        engine.close();
    }

    /**
     * Test concurrent evaluation of different scripts from multiple threads
     */
    @Test