First rev of Safe DOM

tests/html/utils.dart

Index: tests/html/utils.dart
diff --git a/tests/html/utils.dart b/tests/html/utils.dart
index 24e77117db277415330e0f9fe225c6f664d4c552..db2a8b2853d3a7683ad87e6156d0174f96a1725d 100644
--- a/tests/html/utils.dart
+++ b/tests/html/utils.dart
@@ -93,3 +93,39 @@ verifyGraph(expected, actual) {
 
   walk('', expected, actual);
 }
+
+
+/**
+ * Sanitizer which does nothing.
+ */
+class NullTreeSanitizer implements NodeTreeSanitizer {
+  void sanitizeTree(Node node) {}
+}
+
+
+/**
+ * Validate that two DOM trees are equivalent.
+ */
+void validateNodeTree(Node a, Node b, [String path = '']) {
+  path = '${path}${a.runtimeType}';
+  expect(a.nodeType, b.nodeType, reason: '$path nodeTypes differ');
+  expect(a.nodeValue, b.nodeValue, reason: '$path nodeValues differ');
+  expect(a.text, b.text, reason: '$path texts differ');
+  expect(a.nodes.length, b.nodes.length, reason: '$path nodes.lengths differ');
+
+  if (a is Element) {
+    Element bE = b;
+    Element aE = a;
+
+    expect(aE.tagName, bE.tagName, reason: '$path tagNames differ');
+    expect(aE.attributes.length, bE.attributes.length,
+        reason: '$path attributes.lengths differ');
+    for (var key in aE.attributes.keys) {
+      expect(aE.attributes[key], bE.attributes[key],
+          reason: '$path attribute [$key] values differ');
+    }
+  }
+  for (var i = 0; i < a.nodes.length; ++i) {
+    validateNodeTree(a.nodes[i], b.nodes[i], '$path[$i].');
+  }
+}