diff --git a/tox.ini b/tox.ini
index ba4c882f2..9fb2400d3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -50,6 +50,7 @@ extras =
     test
 commands =
     python --version
+    python setup.py build_ext -i
     pytest -v --durations=5 --maxfail=10 {posargs}
 
 [testenv:test-eg]