1 files changed, 1 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index f6e1b6e1..d4c3022b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ envlist = py27,pypy,py34,py35,py36,py37,docs,pep8,py3pep8
 [testenv]
 extras =
    test
+   idna: idna
 deps =
     # This must be kept in sync with Jenkinsfile and .travis/install.sh
     coverage