diff --git a/tox.ini b/tox.ini
index 3869a41..316fcc1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -27,8 +27,12 @@ allowlist_externals =
     /bin/bash
 ; changedir =
 ;     tests
+#
 # https://tox.readthedocs.io/en/latest/config.html#conf-deps
+# https://tox.readthedocs.io/en/latest/example/basic.html#a-simple-tox-ini-default-environments
+#
 deps =
+    -rrequirements.txt
     unittest2
     flake8
     virtualenv