diff --git a/testing/web-platform/tests/urlpattern/resources/urlpatterntestdata.json b/testing/web-platform/tests/urlpattern/resources/urlpatterntestdata.json
index 6138b30cdf5e4..867611baddbb5 100644
--- a/testing/web-platform/tests/urlpattern/resources/urlpatterntestdata.json
+++ b/testing/web-platform/tests/urlpattern/resources/urlpatterntestdata.json
@@ -2359,5 +2359,73 @@
     "expected_match": {
       "protocol": { "input": "foobar", "groups": { "name": "foobar" }}
     }
+  },
+  {
+    "pattern": [{ "hostname": "bad hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad#hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad%hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad/hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad\\:hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad<hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad>hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad?hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad@hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad[hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad]hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad\\\\hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad^hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad|hostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad\nhostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad\rhostname" }],
+    "expected_obj": "error"
+  },
+  {
+    "pattern": [{ "hostname": "bad\thostname" }],
+    "expected_obj": "error"
   }
 ]