console.error when using unknown attributes in templates.

sky/tests/framework/templates.sky

Index: sky/tests/framework/templates.sky
diff --git a/sky/tests/framework/templates.sky b/sky/tests/framework/templates.sky
index 016d124b6ea5661c1caddef4c99db938e86d0853..f34657159ac810eae5fc92765dddcf9728a1b3f4 100644
--- a/sky/tests/framework/templates.sky
+++ b/sky/tests/framework/templates.sky
@@ -120,11 +120,11 @@ describe("SkyElement", function() {
     var inside = element.shadowRoot.getElementById("inside");
     Promise.resolve().then(function() {
       assert.equal(inside.textContent, 10);
-      assert.equal(inside.attr, 10);
+      assert.equal(inside.lang, 10);
       element.value = 20;
     }).then(function() {
       assert.equal(inside.textContent, 20);
-      assert.equal(inside.attr, 20);
+      assert.equal(inside.lang, 20);
       done();
     }).catch(function(e) {
       done(e);