diff --git a/tests/scripts/check_names.py b/tests/scripts/check_names.py
index ef67694..e6a38ba 100755
--- a/tests/scripts/check_names.py
+++ b/tests/scripts/check_names.py
@@ -342,7 +342,7 @@
         * exc_files: A List of relative filepaths for excluded files.
         """
         accumulator = set()
-        all_wildcards = include_wildcards + exclude_wildcards
+        all_wildcards = include_wildcards + (exclude_wildcards or [])
         for wildcard in all_wildcards:
             accumulator = accumulator.union(glob.iglob(wildcard))