diff --git a/tox.ini b/tox.ini
index 11eee8bb..553cc4fc 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,6 +2,9 @@
 envlist=
     coveralls, pylint, flake8, pydocstyle, 2.7, 3.5, 3.6, 3.7, 3.8, 3.9, pypy2, pypy3
 
+[pytest]
+testpaths = tests/unit
+
 [testenv]
 deps=
     pytest