downloader = network.get(2);
userCredentials = NetworkTestUtil.generateRandomCredentials();
// make the two clients ignore each other
uploader.getConnection().getPeer().setObjectDataReply(new DenyingMessageReplyHandler());
downloader.getConnection().getPeer().setObjectDataReply(new DenyingMessageReplyHandler());
// create the roots and the file manager
File rootUploader = new File(System.getProperty("java.io.tmpdir"), NetworkTestUtil.randomString());
uploaderRoot = rootUploader.toPath();
File rootDownloader = new File(System.getProperty("java.io.tmpdir"), NetworkTestUtil.randomString());