--- a/tests/md5sum.py	Thu Jun 15 11:10:51 2017 -0700
+++ b/tests/md5sum.py	Thu Jun 15 12:49:13 2017 -0400
@@ -34,7 +34,7 @@
 
     m = md5()
     try:
-        for data in iter(lambda: fp.read(8192), ''):
+        for data in iter(lambda: fp.read(8192), b''):
             m.update(data)
     except IOError as msg:
         sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))