Adding unittest2 for Python <= 2.6

dev-requirements.txt

@@ -1,2 +1,6 @@
 coverage==4.0
+linecache2==1.0.0
 nose==1.3.7
+six==1.9.0
+traceback2==1.4.0
+unittest2==1.1.0

tests.py

@@ -25,7 +25,8 @@ from jsonrpclib.SimpleJSONRPCServer import SimpleJSONRPCServer
 from jsonrpclib.SimpleJSONRPCServer import SimpleJSONRPCRequestHandler
 import socket
 import tempfile
-import unittest
+import sys
+
 import os
 try:
     import json
@@ -33,6 +34,11 @@ except ImportError:
     import simplejson as json
 from threading import Thread
 
+if sys.version_info < (2, 7):
+    import unittest2 as unittest
+else:
+    import unittest
+
 PORTS = range(8000, 8999)