Rewrite CharacterData-deleteData.html to be more extensible.

tests/wpt/web-platform-tests/dom/nodes/CharacterData-deleteData.html

@@ -7,22 +7,32 @@
 <script src="/resources/testharnessreport.js"></script>
 <div id="log"></div>
 <script>
-function testNode(node) {
+function testNode(create, type) {
   test(function() {
+    var node = create()
+    assert_equals(node.data, "test")
+
     assert_throws("INDEX_SIZE_ERR", function() { node.deleteData(5, 10) })
     assert_throws("INDEX_SIZE_ERR", function() { node.deleteData(5, 0) })
+  }, type + ".deleteData() out of bounds")
+
+  test(function() {
+    var node = create()
+    assert_equals(node.data, "test")
+
     node.deleteData(2, 10)
     assert_equals(node.data, "te")
-  })
+  }, type + ".deleteData() at the end")
+
   test(function() {
-    node.data = "test"
+    var node = create()
     assert_equals(node.data, "test")
+
     node.deleteData(1, 1)
     assert_equals(node.data, "tst")
-  })
+  }, type + ".deleteData() in the middle")
 }
-test(function() {
+
-  testNode(document.createTextNode("test"))
+testNode(function() { return document.createTextNode("test") }, "Text")
-  testNode(document.createComment("test"))
+testNode(function() { return document.createComment("test") }, "Comment")
-})
 </script>