diff -r 9c28f3236677 -r c4217a046b62 tests/run-tests.py
--- a/tests/run-tests.py	Tue Apr 14 16:18:11 2015 -0400
+++ b/tests/run-tests.py	Tue Apr 14 16:21:10 2015 -0400
@@ -1304,7 +1304,7 @@
                         rename(test.errpath, '%s.out' % test.path)
                     accepted = True
             if not accepted and not failed:
-                self.faildata[test.name] = ''.join(lines)
+                self.faildata[test.name] = b''.join(lines)
 
         return accepted