diff --git a/tox.ini b/tox.ini
index 73c7671..dbc2a0e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,7 +23,7 @@ deps = nose
        hypothesis>4
        python-barcode
 commands = pytest --cov escpos
-passenv = ESCPOS_CAPABILITIES_PICKLE_DIR ESCPOS_CAPABILITIES_FILE CI TRAVIS TRAVIS_* APPVEYOR APPVEYOR_* CODECOV_*
+passenv = ESCPOS_CAPABILITIES_PICKLE_DIR, ESCPOS_CAPABILITIES_FILE, CI, TRAVIS, TRAVIS_*, APPVEYOR, APPVEYOR_*, CODECOV_*
 
 [testenv:docs]
 basepython = python