private void delete(File f) {
        if (f.isDirectory()) {
            for (File file : f.listFiles()) {
                delete(file);
            }
        }
        f.delete();
    }
This class sets up a zookeeper server, such that we can test fleetcontroller zookeeper parts without stubbing in the client.
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/ZooKeeperTestServer.java