diff --git a/url/urltestdata.json b/url/urltestdata.json
index 86560b8f2f6aa3..3e3137bf392133 100644
--- a/url/urltestdata.json
+++ b/url/urltestdata.json
@@ -5564,6 +5564,63 @@
     "search": "",
     "hash": ""
   },
+  "# Windows drive letter quirk in the file slash state",
+  {
+    "input": "/c:/foo/bar",
+    "base": "file:///c:/baz/qux",
+    "href": "file:///c:/foo/bar",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/c:/foo/bar",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "/c|/foo/bar",
+    "base": "file:///c:/baz/qux",
+    "href": "file:///c:/foo/bar",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/c:/foo/bar",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "file:\\c:\\foo\\bar",
+    "base": "file:///c:/baz/qux",
+    "href": "file:///c:/foo/bar",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/c:/foo/bar",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "/c:/foo/bar",
+    "base": "file://host/path",
+    "href": "file:///c:/foo/bar",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/c:/foo/bar",
+    "search": "",
+    "hash": ""
+  },
   "# Windows drive letter quirk with not empty host",
   {
     "input": "file://example.net/C:/",