diff --git a/tox.ini b/tox.ini
index beca84c5..b621d916 100644
--- a/tox.ini
+++ b/tox.ini
@@ -28,6 +28,8 @@ setenv =
     TEST_IDEMPOTENCE=false
     VIRTUAL_ENV={envdir}
     WORKING_DIR={toxinidir}
+    # bug#1682108
+    PYTHONPATH={envsitepackagesdir}
 
 
 [testenv:docs]