diff --git a/src/emuvim/dcemulator/net.py b/src/emuvim/dcemulator/net.py
index da546ab..bc54293 100755
--- a/src/emuvim/dcemulator/net.py
+++ b/src/emuvim/dcemulator/net.py
@@ -5,13 +5,13 @@
 import logging
 
 import site
+import time
 from subprocess import Popen
 import os
 
 from mininet.net import Dockernet
-from mininet.node import Controller, OVSSwitch, OVSKernelSwitch, Switch, Docker, Host, RemoteController
+from mininet.node import Controller, DefaultController, OVSSwitch, OVSKernelSwitch, Docker, RemoteController
 from mininet.cli import CLI
-from mininet.log import setLogLevel, info, debug
 from mininet.link import TCLink
 import networkx as nx
 from emuvim.dcemulator.monitoring import DCNetworkMonitor
@@ -27,7 +27,7 @@
     This class is used by topology definition scripts.
     """
 
-    def __init__(self, dc_emulation_max_cpu=1.0, **kwargs):
+    def __init__(self, controller=RemoteController, dc_emulation_max_cpu=1.0, **kwargs):
         """
         Create an extended version of a Dockernet network
         :param dc_emulation_max_cpu: max. CPU time used by containers in data centers
@@ -38,20 +38,20 @@
 
         # call original Docker.__init__ and setup default controller
         Dockernet.__init__(
-            self, controller=RemoteController, switch=OVSKernelSwitch, **kwargs)
-
-        # ass a remote controller to be able to use Ryu
-        self.addController('c0', controller=RemoteController)
-
-        # graph of the complete DC network
-        self.DCNetwork_graph=nx.DiGraph()
-
-        # monitoring agent
-        self.monitor_agent = DCNetworkMonitor(self)
+            self, switch=OVSKernelSwitch, **kwargs)
 
         # start Ryu controller
         self.startRyu()
 
+        # add a remote controller to be able to use Ryu
+        self.addController('c0', controller=controller)
+
+        # graph of the complete DC network
+        self.DCNetwork_graph = nx.DiGraph()
+
+        # monitoring agent
+        self.monitor_agent = DCNetworkMonitor(self)
+
         # initialize resource model registrar
         self.rm_registrar = ResourceModelRegistrar(dc_emulation_max_cpu)
 
@@ -215,5 +215,6 @@
         ryu_option = '--ofp-tcp-listen-port'
         ryu_of_port = '6653'
         ryu_cmd =  'ryu-manager'
-        FNULL = open(os.devnull, 'w')
-        self.ryu_process = Popen([ryu_cmd, ryu_path, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
\ No newline at end of file
+        FNULL = open("/tmp/ryu.log", 'w')
+        self.ryu_process = Popen([ryu_cmd, ryu_path, ryu_path2, ryu_option, ryu_of_port], stdout=FNULL, stderr=FNULL)
+        time.sleep(1)
\ No newline at end of file
diff --git a/src/emuvim/test/base.py b/src/emuvim/test/base.py
index f652259..13ace1b 100644
--- a/src/emuvim/test/base.py
+++ b/src/emuvim/test/base.py
@@ -8,6 +8,7 @@
 import docker
 from emuvim.dcemulator.net import DCNetwork
 from mininet.clean import cleanup
+from mininet.node import Controller
 
 class SimpleTestTopology(unittest.TestCase):
     """
@@ -32,7 +33,7 @@
         Creates a Mininet instance and automatically adds some
         nodes to it.
         """
-        self.net = net = DCNetwork()
+        self.net = DCNetwork()
 
         # add some switches
         for i in range(0, nswitches):
diff --git a/src/emuvim/test/test_emulator.py b/src/emuvim/test/test_emulator.py
index d552f1f..fb8714a 100755
--- a/src/emuvim/test/test_emulator.py
+++ b/src/emuvim/test/test_emulator.py
@@ -40,7 +40,7 @@
         # stop Mininet network
         self.stopNet()
 
-    @unittest.skip("disabled to test if CI fails because this is the first test.")
+    #@unittest.skip("disabled to test if CI fails because this is the first test.")
     def testMultipleDatacenterDirect(self):
         """
         Create a two data centers and interconnect them.
@@ -57,7 +57,6 @@
         assert(len(self.getDockernetContainers()) == 0)
         assert(len(self.net.hosts) == 2)
         assert(len(self.net.switches) == 2)
-        time.sleep(5)
         # check connectivity by using ping
         assert(self.net.ping([self.h[0], self.h[1]]) <= 0.0)
         # stop Mininet network