tests/run-tests.py

--- a/tests/run-tests.py	Wed Sep 12 19:14:28 2018 -0400
+++ b/tests/run-tests.py	Wed Sep 12 21:32:08 2018 -0400
@@ -3118,8 +3118,8 @@
     def _checktools(self):
         """Ensure tools required to run tests are present."""
         for p in self.REQUIREDTOOLS:
-            if os.name == 'nt' and not p.endswith('.exe'):
-                p += '.exe'
+            if os.name == 'nt' and not p.endswith(b'.exe'):
+                p += b'.exe'
             found = self._findprogram(p)
             if found:
                 vlog("# Found prerequisite", p, "at", found)