diff --git a/tests.py b/tests.py
index 851e0abc8..3e16e1c71 100644
--- a/tests.py
+++ b/tests.py
@@ -4562,6 +4562,7 @@ def _test_source_contains_no_tabs():
             if '\t' in source_str:
                 print(source_file + ' contains tabs')
                 assert False
+        break
 
 
 def _test_checkbox_names():