waiter.interrupt();

    // This should wake up waiter1 and cause the waiter1 node to be removed.
    waiter.join();
    future.set(null);
    poller.join();
  }

  public void testToString_allUnique() throws Exception {
    // Two futures should not have the same toString, to avoid people asserting on it
    assertThat(SettableFuture.create().toString()).isNotEqualTo(SettableFuture.create().toString());
  }