called = true;
            }
          }
        };
    addCallback(f, callback, directExecutor());
    f.cancel(true);
  }

  public void testThrowErrorFromGet() {
    Error error = new AssertionError("ASSERT!");
    ListenableFuture<String> f = UncheckedThrowingFuture.throwingError(error);
    MockCallback callback = new MockCallback(error);