//lets execute the transaction...
Future<Object> tx = executeTransaction(cache(0), key);
//it waits until all nodes has replied. then, we change the topology ID and let it collect the responses.
nodeARpcManager.waitForCommandToBlock();
nodeAController.topologyManager.stopBlocking(BlockingLocalTopologyManager.LatchType.CONSISTENT_HASH_UPDATE);
awaitForTopology(currentTopologyId + 2, cache(0));
nodeARpcManager.stopBlocking();
assertNull("Wrong put() return value.", tx.get());