diff --git a/test/karma.config.js b/test/karma.config.js
index 0d7e250245..5f1a0f4f5c 100644
--- a/test/karma.config.js
+++ b/test/karma.config.js
@@ -18,6 +18,10 @@ module.exports = function(karma) {
       runInParent: true
     },
     files: [
+      {
+        pattern: 'https://cdn.polyfill.io/v2/polyfill.min.js?features=URL|gated',
+        watched: false
+      },
       {
         pattern: 'module-global.js',
         watched: false
@@ -86,16 +90,16 @@ module.exports = function(karma) {
       SL_Firefox: {
         base: 'SauceLabs',
         browserName: 'firefox'
-      // },
+      },
       // SL_Edge: {
       //   base: 'SauceLabs',
       //   platform: 'Windows 10',
       //   browserName: 'MicrosoftEdge'
       // },
-      // SL_Safari: {
-      //   base: 'SauceLabs',
-      //   platform: 'macos 10.12',
-      //   browserName: 'safari'
+      SL_Safari: {
+        base: 'SauceLabs',
+        platform: 'macos 10.12',
+        browserName: 'safari'
       }
     };
     karma.set({