diff --git a/url/urltestdata.json b/url/urltestdata.json
index a82f1111a5b6d9..fe13d3f1edfc29 100644
--- a/url/urltestdata.json
+++ b/url/urltestdata.json
@@ -5423,6 +5423,105 @@
     "search": "?chai",
     "hash": ""
   },
+  "# Windows drive letter handling with the 'file:' base URL",
+  {
+    "input": "C|",
+    "base": "file://host/dir/file",
+    "href": "file:///C:",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/C:",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "C|#",
+    "base": "file://host/dir/file",
+    "href": "file:///C:#",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/C:",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "C|?",
+    "base": "file://host/dir/file",
+    "href": "file:///C:?",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/C:",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "C|/",
+    "base": "file://host/dir/file",
+    "href": "file:///C:/",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/C:/",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "C|\\",
+    "base": "file://host/dir/file",
+    "href": "file:///C:/",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "",
+    "hostname": "",
+    "port": "",
+    "pathname": "/C:/",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "C",
+    "base": "file://host/dir/file",
+    "href": "file://host/dir/C",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "host",
+    "hostname": "host",
+    "port": "",
+    "pathname": "/dir/C",
+    "search": "",
+    "hash": ""
+  },
+  {
+    "input": "C|a",
+    "base": "file://host/dir/file",
+    "href": "file://host/dir/C|a",
+    "protocol": "file:",
+    "username": "",
+    "password": "",
+    "host": "host",
+    "hostname": "host",
+    "port": "",
+    "pathname": "/dir/C|a",
+    "search": "",
+    "hash": ""
+  },
   "# Windows drive letter quirk with not empty host",
   {
     "input": "file://example.net/C:/",