diff --git a/test/globals.js b/test/globals.js
new file mode 100644
index 0000000..4b7de5c
--- /dev/null
+++ b/test/globals.js
@@ -0,0 +1,2 @@
+// global variables for karma
+window.process = { env: { NODE_ENV: 'production'} };
\ No newline at end of file
diff --git a/test/karma.conf.js b/test/karma.conf.js
index d639b36..6dea6fe 100644
--- a/test/karma.conf.js
+++ b/test/karma.conf.js
@@ -43,6 +43,7 @@ module.exports = function(config) {
     },
 
     files: [
+      'test/globals.js',
       'fastdom.js',
       'extensions/fastdom-promised.js',
       'extensions/fastdom-sandbox.js',