added preliminary ShadowDOM tests

tests/html/shadow_dom_test.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#library('ShadowDOMTest');
+#import('../../lib/unittest/unittest.dart');
+#import('../../lib/unittest/html_config.dart');
+#import('dart:html');
+
+main() {
+  useHtmlConfiguration();
+  
+  group("ShadowDOM tests", () {
+
+    var div1, div2, sr, para1, para2; 
+
+    setUp(() {
+      para1 = new ParagraphElement();

[Jacob, 2012/06/26 18:22:57]

avoid variable names with abbreviations such as 
para
and
sr

div is sufficiently common that it is fine but
sr should be shadowRoot or shadow.

[samhop, 2012/06/26 22:38:34]

fixed by switching to shadowRoot and paragraph1, paragraph2

On 2012/06/26 18:22:57, Jacob wrote:

+      para2 = new ParagraphElement();
+      [para1, para2].forEach( (p) {
+        p.classes.add("foo");

[Jacob, 2012/06/26 18:22:57]

odd spacing.
Also, 
might as well just use
for (var p in [para1, para2]) {
  p.classes.add("foo");
}

[Emily Fortuna, 2012/06/26 18:30:53]

Or just 
[para1, para2].forEach( (p) { p.classes.add("foo");}); 
if you feel like you need to do it functionally. :-)

[samhop, 2012/06/26 22:38:34]

Thank you for your respect for *proper* programming, Emily :). Fixed.

+      });

[Siggi Cherem (dart-lang), 2012/06/26 18:28:30]

nit: I prefer here just the 2 lines:
para1.classes.add('foo');
para2.classes.add('foo');

(the current way ends up having more code for the same purpose)

[samhop, 2012/06/26 22:38:34]

Done.

+      div1 = new DivElement();
+      div2 = new DivElement();
+      div1.classes.add('foo');
+      sr = new ShadowRoot(div2);
+      sr.nodes.add(para1);
+      // No constructor for ContentElement exists yet.
+      // See http://code.google.com/p/dart/issues/detail?id=3870.
+      sr.nodes.add(new Element.tag('content'));
+      div2.nodes.add(para2);
+      document.body.nodes.add(div1);
+      document.body.nodes.add(div2);
+    });
+
+    test("Shadowed nodes aren't visible to queries from outside ShadowDOM", () {
+           expect(queryAll('.foo'), equals([div1, para2]));

[Siggi Cherem (dart-lang), 2012/06/26 18:28:30]

<< (only +2 indent)

[samhop, 2012/06/26 22:38:34]

Done.

+    });
+
+    test("Parent node of a shadow root must be null.", () {

[Siggi Cherem (dart-lang), 2012/06/26 18:28:30]

nit: we try to consistently prefer ' over " unless your string contains ' in
them. (replace here, below, and in some places where you have "foo" or ".foo")

[samhop, 2012/06/26 22:38:34]

Done.

+      expect(sr.parent, isNull);
+    });
+
+    
+    // TODO(samhop): test that <content> and <content select="foo"> and
+    // <shadow>
+    // work properly. This is blocked on having a good way to do browser
+    // rendering tests.
+
+    test("Querying in shadowed fragment respects the shadow boundary.", () {
+      expect(sr.queryAll(".foo"), equals([para1]));
+    }); 
+  });
+}