--- a/tests/run-tests.py	Mon Nov 20 14:30:54 2017 -0500
+++ b/tests/run-tests.py	Sun Nov 19 04:10:55 2017 +0100
@@ -969,7 +969,7 @@
         r.append((self._escapepath(self._testtmp), b'$TESTTMP'))
 
         testdir = os.path.dirname(self.path)
-        replacementfile = os.path.join(testdir, 'common-pattern.py')
+        replacementfile = os.path.join(testdir, b'common-pattern.py')
 
         if os.path.exists(replacementfile):
             data = {}