diff --git a/tox.ini b/tox.ini
index c01f513..7e3f601 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,28 +1,29 @@
 [tox]
 envlist=flake8,mypy,py3
 
 [testenv]
+extras =
+  testing
 deps =
   swh.core[http] >= 0.0.61
-  .[testing]
   pytest-cov
   dev: ipdb
 commands =
   pytest \
   !dev: --cov={envsitepackagesdir}/swh/lister/ --cov-branch \
          {envsitepackagesdir}/swh/lister/ {posargs}
 
 [testenv:flake8]
 skip_install = true
 deps =
   flake8
 commands =
   {envpython} -m flake8
 
 [testenv:mypy]
-skip_install = true
+extras =
+  testing
 deps =
-  .[testing]
   mypy
 commands =
   mypy swh