diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index da55a3a156..0c4cdac528 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -272,7 +272,7 @@ def main():
     if tests:
         # Individual tests have been specified. Run specified tests that exist
         # in the ALL_SCRIPTS list. Accept the name with or without .py extension.
-        tests = [re.sub("\.py$", "", test) + ".py" for test in tests]
+        tests = [test + ".py" if ".py" not in test else test for test in tests]
         for test in tests:
             if test in ALL_SCRIPTS:
                 test_list.append(test)