dequelabs
diff --git a/‎lib/core/utils/parse-crossorigin-stylesheet.js‎
Lines changed: 4 additions & 0 deletions b/‎lib/core/utils/parse-crossorigin-stylesheet.js‎
Lines changed: 4 additions & 0 deletions
diff --git a/‎test/core/utils/parse-crossorigin-stylesheet.js‎
Lines changed: 31 additions & 0 deletions b/‎test/core/utils/parse-crossorigin-stylesheet.js‎
Lines changed: 31 additions & 0 deletions
@@ -20,6 +20,10 @@ function parseCrossOriginStylesheet(
   importedUrls,
   isCrossOrigin
 ) {
+  if (url === null || url === undefined) {
+    return Promise.resolve();
+  }
+
   /**
    * Add `url` to `importedUrls`
    */
 
@@ -89,4 +89,35 @@ describe('axe.utils.parseCrossOriginStylesheet', () => {
         done();
       });
   });
+
+  it('returns empty results when url is nullish', function (done) {
+    this.timeout(axe.constants.preload.timeout + 1000);
+
+    var importUrl = null;
+    var options = {
+      rootNode: document,
+      shadowId: undefined,
+      convertDataToStylesheet: convertDataToStylesheet,
+      rootIndex: 1
+    };
+    var priority = [1, 0];
+    var importedUrls = [];
+    var isCrossOriginRequest = true;
+
+    axe.utils
+      .parseCrossOriginStylesheet(
+        importUrl,
+        options,
+        priority,
+        importedUrls,
+        isCrossOriginRequest
+      )
+      .then(function (data) {
+        assert.isUndefined(data);
+        done();
+      })
+      .catch(function (err) {
+        done(err);
+      });
+  });
 });