Added test utilities file with delete_all_flows
diff --git a/tests/testutils.py b/tests/testutils.py
new file mode 100644
index 0000000..b4c9e28
--- /dev/null
+++ b/tests/testutils.py
@@ -0,0 +1,16 @@
+
+import oftest.controller as controller
+import oftest.cstruct as ofp
+import oftest.message as message
+import oftest.dataplane as dataplane
+import oftest.action as action
+import logging
+
+def delete_all_flows(controller, logger):
+    logger.info("Deleting all flows")
+    msg = message.flow_mod()
+    msg.match.wildcards = ofp.OFPFW_ALL
+    msg.command = ofp.OFPFC_DELETE
+    msg.buffer_id = 0xffffffff
+    return controller.message_send(msg)
+