diff --git a/selftests/core/__init__.py b/selftests/core/__init__.py
index b53572f..dba2fb2 100644
--- a/selftests/core/__init__.py
+++ b/selftests/core/__init__.py
@@ -57,10 +57,10 @@ def check_calls(self, acts, exps):
         """
         i = 0
         for call in acts:
-            if exps[i] in str(call):
+            while exps[i] in str(call):
                 i += 1
                 if len(exps) == i:
-                    break
+                    return
         self.assertEqual(i, len(exps), "Some calls were not present at all or"
                          " in the expected order. Expected:\n%s\n\nActual:\n%s"
                          % ("\n".join(str(_) for _ in exps),