Index: tests/pybin/tools.py
===================================================================
--- tests/pybin/tools.py	(revision 2bb2d3f17461ce23421cbb1b925d154dad123cec)
+++ tests/pybin/tools.py	(revision 09bbe7841288d33abb41ab7fe24ce076aeefae6a)
@@ -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
Index: tests/test.py
===================================================================
--- tests/test.py	(revision 2bb2d3f17461ce23421cbb1b925d154dad123cec)
+++ tests/test.py	(revision 09bbe7841288d33abb41ab7fe24ce076aeefae6a)
@@ -207,5 +207,5 @@
 		else:
 			if os.stat(out_file).st_size < 1048576:
-				with open (out_file, "r") as myfile:
+				with open (out_file, "r", encoding='latin-1') as myfile:  # use latin-1 so all chars mean something.
 					error = myfile.read()
 			else: