diff --git a/tox.ini b/tox.ini
index 6dcc230..2257010 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,20 +8,20 @@ max-line-length = 110
 
 [testenv:flake8]
 deps = flake8
-commands = flake8 bootstrapvz/ --exclude=minify_json.py
+commands = flake8 bootstrapvz/ --exclude=minify_json.py {posargs}
 
 [testenv:unit]
 deps =
     nose
     nose-cov
-commands = nosetests -v tests/unit --with-coverage --cover-package=bootstrapvz --cover-inclusive
+commands = nosetests -v tests/unit --with-coverage --cover-package=bootstrapvz --cover-inclusive {posargs}
 
 [testenv:integration]
 deps =
     nose
     Pyro4 >= 4.30
     pyvbox >= 0.2.0
-commands = nosetests -v tests/integration --with-coverage --cover-package=bootstrapvz --cover-inclusive
+commands = nosetests -v tests/integration --with-coverage --cover-package=bootstrapvz --cover-inclusive {posargs}
 
 [testenv:docs]
 changedir = docs