diff --git a/fail2ban/tests/filtertestcase.py b/fail2ban/tests/filtertestcase.py
index bc043373..fa9340ca 100644
--- a/fail2ban/tests/filtertestcase.py
+++ b/fail2ban/tests/filtertestcase.py
@@ -54,7 +54,7 @@ def open(*args):
 		# ~50kB buffer should be sufficient for all tests here.
 		args = args + (50000,)
 	if sys.version_info >= (3,):
-		return fopen(*args, encoding='utf-8', errors='ignore')
+		return fopen(*args, **{'encoding': 'utf-8', 'errors': 'ignore'})
 	else:
 		return fopen(*args)