diff --git a/Lib/test/test_netrc.py b/Lib/test/test_netrc.py
index a6b4bc47a32..3cca1e8ff1a 100644
--- a/Lib/test/test_netrc.py
+++ b/Lib/test/test_netrc.py
@@ -10,7 +10,7 @@ def make_nrc(self, test_data):
         mode = 'w'
         if sys.platform != 'cygwin':
             mode += 't'
-        with open(temp_filename, mode) as fp:
+        with open(temp_filename, mode, encoding="utf-8") as fp:
             fp.write(test_data)
         try:
             nrc = netrc.netrc(temp_filename)