diff --git a/tests/wpt/urltestdata.json b/tests/wpt/urltestdata.json
index 9dbe5456a..0ebaf4cd4 100644
--- a/tests/wpt/urltestdata.json
+++ b/tests/wpt/urltestdata.json
@@ -9992,5 +9992,101 @@
     "pathname": "/",
     "search": "",
     "hash": ""
+  },
+  "# Non-special URL and backslashes",
+  {
+    "input": "non-special:\\\\opaque",
+    "base": null,
+    "href": "non-special:\\\\opaque",
+    "origin": "null",
+    "protocol": "non-special:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "\\\\opaque",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "non-special:\\\\opaque/path",
+    "base": null,
+    "href": "non-special:\\\\opaque/path",
+    "origin": "null",
+    "protocol": "non-special:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "\\\\opaque/path",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "non-special:\\\\opaque\\path",
+    "base": null,
+    "href": "non-special:\\\\opaque\\path",
+    "origin": "null",
+    "protocol": "non-special:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "\\\\opaque\\path",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "non-special:\\/opaque",
+    "base": null,
+    "href": "non-special:\\/opaque",
+    "origin": "null",
+    "protocol": "non-special:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "\\/opaque",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "non-special:/\\path",
+    "base": null,
+    "href": "non-special:/\\path",
+    "origin": "null",
+    "protocol": "non-special:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/\\path",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "non-special://host\\a",
+    "base": null,
+    "failure": true
+  },
+  {
+    "input": "non-special://host/a\\b",
+    "base": null,
+    "href": "non-special://host/a\\b",
+    "origin": "null",
+    "protocol": "non-special:",
+    "username": "",
+    "password": "",
+    "host": "host",
+    "hostname": "host",
+    "port": "",
+    "pathname": "/a\\b",
+    "search": "",
+    "hash": ""
   }
 ]