MockExecutor mock = new MockExecutor();
    TestExecutor testExecutor = new TestExecutor(mock);
    testExecutor.execute(doNothing());
    mock.assertLastMethodCalled("execute");
  }

  public void testSubmit() throws InterruptedException, ExecutionException {
    {
      MockExecutor mock = new MockExecutor();
      TestExecutor testExecutor = new TestExecutor(mock);
      Future<?> f = testExecutor.submit(doNothing());

                  public TestCloseable call() throws Exception {
                    throw exception;
                  }
                }),
            closingExecutor));
  }

  public void testSubmit() throws Exception {
    ClosingFuture<String> closingFuture =
        ClosingFuture.submit(
                new ClosingCallable<TestCloseable>() {
                  @Override