Mockito mit Java async->sync Konverter

Question

Ich habe eine asynchrone Methode, die ich in eine synchrone Methode mit einem Countdown-Latch umwandle. Ich habe Schwierigkeiten, einen Unit-Test zu schreiben, ohne die Timeout-Funktion von Mockito zu verwenden. Ich kann nicht herausfinden, wie ich die Verifizierungsmethode dazu bringe, auf den Aufruf der asynchronen Methode zu warten:

public interface SyncExchangeService {
    boolean placeOrder(Order order);
}
public interface ExchangeService {
    void placeOrder(Order order, OrderCallback orderResponseCallback);
}

public interface OrderCallback {
    public void onSuccess();
    public void onFailure();
}

public class SyncExchangeServiceAdapter implements SyncExchangeService {
    private ExchangeService exchangeService;

    public SyncExchangeServiceAdapter(ExchangeService exchangeService) {
        this.exchangeService = exchangeService;
    }

    @Override
    public boolean placeOrder(Order order) {

        final CountDownLatch countdownLatch=new CountDownLatch(1);
        final AtomicBoolean result=new AtomicBoolean();
        exchangeService.placeOrder(order, new OrderCallback() {

            @Override
            public void onSuccess() {
                result.set(true);
                countdownLatch.countDown();
            }

            @Override
            public void onFailure(String rejectReason) {
                result.set(false);
                countdownLatch.countDown();
            }
        });
        try {
            countdownLatch.await();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        return result.get();
    }
}

public class SyncExchangeServiceAdapterTest {
    private ExchangeService mockExchange=mock(ExchangeService.class);
    private SyncExchangeServiceAdapter adapter=new SyncExchangeServiceAdapter(mockExchange);
    private Boolean response;
    private ArgumentCaptor<Boolean> callback=CaptorArgumentCaptor.forClass(OrderCallback.class);
    private CountDownLatch latch=new CountDownLatch(1);

    @Test
    public void testPlaceOrderWithSuccess() throws Exception {
        final Order order=mock(Order.class);
         Executors.newSingleThreadExecutor().submit(new Runnable() {
            @Override
            public void run() {
                response=adapter.placeOrder(order);
                latch.countDown();
            }
        });
            verify(mockExchange,timeout(10) ).placeOrder(eq(order), callbackCaptor.capture());
//the timeout method is not really recommended and could also fail randomly if the thread takes more than 10ms

        callbackCaptor.getValue().onSuccess();
        latch.await(1000,TimeUnit.MILLISECONDS);
            assertEquals(true,response);
    }

}