Index: tests/pybin/tools.py
===================================================================
--- tests/pybin/tools.py	(revision eb67b47635ef70468037882e93204c4624478aec)
+++ tests/pybin/tools.py	(revision da9a27cd637fa895351e43051a121e8a2eb9bc94)
@@ -120,5 +120,5 @@
 		return None
 
-	file = open(file, mode)
+	file = open(file, mode, encoding="latin-1") # use latin-1 so all chars mean something.
 	exitstack.push(file)
 	return file