diff --git a/tests/runtests.py b/tests/runtests.py
index 9760300..fbb436d 100644
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -26,7 +26,7 @@ import os
 import sys
 
 def runtests(pacfile, testdata, tests_dir):
-  py_ver = '.'.join([str(x) for x in sys.version_info[0:2]])
+  py_ver = ''.join([str(x) for x in sys.version_info[0:2]])
   try:
     pacparser_module_path = glob.glob(os.path.join(
       tests_dir, '..', 'src', 'pymod', 'build', 'lib*%s' % py_ver))[0]