diff --git a/tox.ini b/tox.ini
index 8dc582a..a22db72 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,19 +1,26 @@
 [tox]
 envlist=flake8,py3
 
 [testenv:py3]
 deps =
   swh.core[http] >= 0.0.61
   .[testing]
   pytest-cov
 commands =
   pytest --cov={envsitepackagesdir}/swh/lister/ --cov-branch \
          {envsitepackagesdir}/swh/lister/ {posargs}
 
+[testenv:py3-dev]
+deps =
+  swh.core[http] >= 0.0.61
+  .[testing]
+  pytest-cov
+commands =
+  pytest {envsitepackagesdir}/swh/lister/ {posargs}
 
 [testenv:flake8]
 skip_install = true
 deps =
   flake8
 commands =
   {envpython} -m flake8