diff --git a/karma.conf.js b/karma.conf.js
index 559aa35..cd34e59 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -20,7 +20,16 @@ var path = require('path');
 
 module.exports = function (config) {
   // This tox venv is setup in the post-install npm step
-  var toxPath = '.tox/py38/lib/python3.8/site-packages/';
+  var toxPath = path.resolve('./.tox/npm');
+  if (!toxPath) {
+      console.error('xStatic libraries not found, please run `tox -e npm`');
+      process.exit(1);
+    }
+    toxPath += '/lib/';
+    toxPath += fs.readdirSync(toxPath).find(function(directory) {
+      return directory.indexOf('python') === 0;
+    });
+    toxPath += '/site-packages/';
   var xstaticPath = toxPath + 'xstatic/pkg/';
 
   config.set({
diff --git a/package.json b/package.json
index a7e5c43..3565920 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "karma-ng-html2js-preprocessor": "1.0.0"
   },
   "scripts": {
-    "postinstall": "if [ ! -d .tox/py38 ]; then tox -epy38 --notest; fi",
+    "postinstall": "if [ ! -d .tox/npm ]; then tox -e npm --notest; fi",
     "lint": "eslint --no-color designatedashboard/static",
     "lintq": "eslint --quiet designatedashboard/static",
     "test": "karma start karma.conf.js --single-run"
diff --git a/tox.ini b/tox.ini
index b872a90..0a758cd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.18.0
-envlist = py3,pep8
+envlist = py3,pep8, npm
 skipsdist = True
 # Automatic envs (pyXX) will only use the python version appropriate to that
 # env and ignore basepython inherited from [testenv] if we set
@@ -19,6 +19,8 @@ setenv = VIRTUAL_ENV={envdir}
          PYTHONDONTWRITEBYTECODE=1
          DJANGO_SETTINGS_MODULE=designatedashboard.settings
 allowlist_externals = find
+                      {toxinidir}/manage.py
+                      npm
 deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
@@ -26,7 +28,13 @@ deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/up
 commands =
   find . -type f -name "*.pyc" -delete
   {toxinidir}/manage.py test designatedashboard --settings=designatedashboard.tests.settings
-passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
+passenv =
+  http_proxy
+  HTTP_PROXY
+  https_proxy
+  HTTPS_PROXY
+  no_proxy
+  NO_PROXY
 
 [testenv:pep8]
 commands = flake8