diff --git a/tox.ini b/tox.ini
--- a/tox.ini
+++ b/tox.ini
@@ -1,10 +1,11 @@
 [tox]
 envlist=flake8,mypy,py3
 
-[testenv:py3]
+[testenv]
 passenv=SWH_KAFKA_ROOT
+extras =
+  testing
 deps =
-  .[testing]
   pytest-cov
 setenv =
   SWH_KAFKA_ROOT = {env:SWH_KAFKA_ROOT:swh/journal/tests/kafka}
@@ -22,9 +23,9 @@
   {envpython} -m flake8
 
 [testenv:mypy]
-skip_install = true
+extras =
+  testing
 deps =
-  .[testing]
   mypy
 commands =
   mypy swh