diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 841aa8f1c5b..86b5ac0f31e 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -113,12 +113,6 @@
             "url": "/_mozilla/mozilla/caption.html"
           }
         ],
-        "mozilla/characterdata.html": [
-          {
-            "path": "mozilla/characterdata.html",
-            "url": "/_mozilla/mozilla/characterdata.html"
-          }
-        ],
         "mozilla/child_reparenting.html": [
           {
             "path": "mozilla/child_reparenting.html",
diff --git a/tests/wpt/mozilla/tests/mozilla/characterdata.html b/tests/wpt/mozilla/tests/mozilla/characterdata.html
deleted file mode 100644
index 9e8bb9fd10e..00000000000
--- a/tests/wpt/mozilla/tests/mozilla/characterdata.html
+++ /dev/null
@@ -1,27 +0,0 @@
-<html>
-  <head>
-    <script src="/resources/testharness.js"></script>
-    <script src="/resources/testharnessreport.js"></script>
-  </head>
-  <body>
-    <p>This is the character data</p>
-  </body>
-  <script>
-  test(function() {
-    var a = document.getElementsByTagName('p')[0].childNodes[0];
-    a.data = "This is the character data test, append 資料，更多資料";
-
-    // replace test non-utf8
-    a.replaceData(33, 6, "other");
-    assert_equals(a.data, "This is the character data test, other 資料，更多資料");
-    // replace test non-utf8
-    a.replaceData(44, 2, "文字");
-    assert_equals(a.data, "This is the character data test, other 資料，更多文字");
-
-    // substring test non-utf8
-    assert_equals(a.substringData(12, 4), "char");
-    // substring test utf8
-    assert_equals(a.substringData(39, 2), "資料");
-  });
-  </script>
-</html>
diff --git a/tests/wpt/web-platform-tests/dom/nodes/CharacterData-substringData.html b/tests/wpt/web-platform-tests/dom/nodes/CharacterData-substringData.html
index 1d7288ab3f1..adcce727022 100644
--- a/tests/wpt/web-platform-tests/dom/nodes/CharacterData-substringData.html
+++ b/tests/wpt/web-platform-tests/dom/nodes/CharacterData-substringData.html
@@ -7,7 +7,6 @@
 <script src="/resources/testharnessreport.js"></script>
 <div id="log"></div>
 <script>
-// TODO: non-ASCII strings
 function testNode(create, type) {
   test(function() {
     var node = create()
@@ -101,6 +100,16 @@ function testNode(create, type) {
     assert_equals(node.substringData(0, -1), "test")
     assert_equals(node.substringData(0, -0x100000000 + 2), "te")
   }, type + ".substringData() with negative count")
+
+  test(function() {
+    var node = create()
+    assert_equals(node.data, "test")
+
+    node.data = "This is the character data test, other 資料，更多文字"
+
+    assert_equals(node.substringData(12, 4), "char")
+    assert_equals(node.substringData(39, 2), "資料")
+  }, type + ".substringData() with non-ASCII data")
 }
 
 testNode(function() { return document.createTextNode("test") }, "Text")
