diff --git a/tests/regression_tests/__init__.py b/tests/regression_tests/__init__.py
index dcbac5447a..a887448c11 100644
--- a/tests/regression_tests/__init__.py
+++ b/tests/regression_tests/__init__.py
@@ -1,6 +1,6 @@
 # Test configuration options for regression tests
 config = {
-    'event' : False
+    'event' : False,
     'exe': 'openmc',
     'mpi': False,
     'mpiexec': 'mpiexec',