diff --git a/tests/conftest.py b/tests/conftest.py
index 2d4241806c17b30c80b2b3c93a4c02857f84b59f..eb37d95f302dce8a5ad3b31ebe343e8b80f86a13 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -250,7 +250,7 @@ class TransitionsStateMachineTester(StateMachineTester):
 
 class ModelStateMachineTester(StateMachineTester):
     """
-    Abstract base class for a class for testing state models using state machines.
+    Abstract base class for testing state models using state machines.
 
     The ``assert_state`` method has to be implemented in concrete classes,
     and the `machine` fixture must also be provided.