diff --git a/package-lock.json b/package-lock.json
index 1e55ad8..8f67d72 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "postcss-less",
-  "version": "5.0.0",
+  "version": "6.0.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index bfd2869..572afd1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "postcss-less",
-  "version": "5.0.0",
+  "version": "6.0.0",
   "description": "LESS parser for PostCSS",
   "license": "MIT",
   "repository": "shellscape/postcss-less",
diff --git a/test/integration.test.js b/test/integration.test.js
index 2da358c..f09d31a 100644
--- a/test/integration.test.js
+++ b/test/integration.test.js
@@ -22,6 +22,7 @@ for (const site of sites) {
     const $ = cheerio.load(html);
 
     const hrefs = $('head link[rel=stylesheet]')
+      .filter((index, sheet) => !!sheet.attribs.href)
       .map((index, sheet) => {
         let { href } = sheet.attribs;