diff --git a/tox.ini b/tox.ini
index 763892a..55b072d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,30 +1,31 @@
 [tox]
 envlist=flake8,mypy,py3
 
 [testenv]
 extras =
   testing
 deps =
   pytest-cov
+  dev: ipdb
 commands =
   pytest \
     !slow: --hypothesis-profile=fast \
     slow:  --hypothesis-profile=slow \
          --cov={envsitepackagesdir}/swh/storage \
          {envsitepackagesdir}/swh/storage \
          --cov-branch {posargs}
 
 [testenv:flake8]
 skip_install = true
 deps =
   flake8
 commands =
   {envpython} -m flake8
 
 [testenv:mypy]
 extras =
   testing
 deps =
   mypy
 commands =
   mypy swh