diff --git a/tox.ini b/tox.ini
index d51853c..a6e6fca 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,6 +11,7 @@ deps = nose
        pytest-cov
        pytest-mock
        hypothesis
+       viivakoodi
 commands = py.test --cov escpos
 
 [testenv:docs]