diff --git a/tox.ini b/tox.ini
index 8d0ed8044852884f3ebbcdf1ad26355b61165303..ec89c8510ced964dcd1009ec284007fecf2b9a9f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,8 +2,9 @@
 envlist=flake8,mypy,py3
 
 [testenv]
+extras =
+  testing
 deps =
-  .[testing]
   pytest-cov
 commands =
   pytest --cov={envsitepackagesdir}/swh/model \
@@ -18,9 +19,9 @@ commands =
   {envpython} -m flake8
 
 [testenv:mypy]
-skip_install = true
+extras =
+  testing
 deps =
-  .[testing]
   mypy
 commands =
   mypy swh