```diff
diff --git a/conftest.py b/conftest.py
index c7669aa..16b0484 100644
--- a/conftest.py
+++ b/conftest.py
@@ -31,5 +31,7 @@ def pytest_collection_modifyitems(session, config, items):
     expression = config.getvalue('keyword') or False
     if expression:
         expr_string = ', will filter with "%s"' % expression
+    else:
+        expr_string = ''
     logger.info('Collected %i items%s' % (len(items), expr_string))
 
```