diff --git a/lib/middleware/karma.js b/lib/middleware/karma.js
index 3392096bd..831668324 100644
--- a/lib/middleware/karma.js
+++ b/lib/middleware/karma.js
@@ -179,6 +179,10 @@ var createKarmaMiddleware = function (
             var filePath = file.path
             var fileExt = path.extname(filePath)
 
+            if (!files.included.hasOwnProperty(i)) {
+              continue
+            }
+
             if (!file.isUrl) {
               filePath = filePathToUrlPath(filePath, basePath, urlRoot, proxyPath)