diff --git a/tox.ini b/tox.ini
index 317029f..757db0a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,4 +10,4 @@ addopts = -v --cov rsa --cov-report term-missing
 deps = poetry
 commands =
     poetry install
-    poetry run pytest tests/
+    poetry run pytest --doctest-modules rsa tests/