diff --git a/matemat/webserver/test/test_config.py b/matemat/webserver/test/test_config.py
index 9e13374..e2ad985 100644
--- a/matemat/webserver/test/test_config.py
+++ b/matemat/webserver/test/test_config.py
@@ -241,3 +241,12 @@ class TestConfig(TestCase):
             with self.assertRaises(ValueError):
                 # The filename is only a placeholder, file content is determined by mocking open
                 parse_config_file('test')
+
+    def test_parse_config_not_a_filename(self):
+        """
+        Test type checking for the config filenames
+        """
+        with self.assertRaises(TypeError):
+            parse_config_file(42)
+        with self.assertRaises(TypeError):
+            parse_config_file(['config', 42])