diff --git a/test/unit/base.html b/test/unit/base.html
index 6ffb7ea53f..19724949a3 100644
--- a/test/unit/base.html
+++ b/test/unit/base.html
@@ -29,8 +29,7 @@
 
 setup(function() {
   // Ensure a clean environment for each test.
-  window.Base = Polymer.Base;
-  window.Child = Object.create(Base);
+  window.Child = Object.create(Polymer.Base);
   Child._registerFeatures = function() {
   };
   Child._initFeatures = function() {};
@@ -47,9 +46,9 @@
 suite('addFeature', function() {
 
   test('mixes the feature into Base', function() {
-    assert.notOk(Base.someProperty);
-    Base._addFeature({someProperty: 123});
-    assert.equal(Base.someProperty, 123);
+    assert.notOk(Polymer.Base.someProperty);
+    Polymer.Base._addFeature({someProperty: 123});
+    assert.equal(Polymer.Base.someProperty, 123);
   });
 
 });
diff --git a/test/unit/lazy-register.html b/test/unit/lazy-register.html
index 0d07bc8a3a..0f03f34758 100644
--- a/test/unit/lazy-register.html
+++ b/test/unit/lazy-register.html
@@ -76,15 +76,15 @@
 suite('lazy-register', function() {
 
   test('not registered until first instance', function() {
-    assert.isFalse(XLazy.prototype.registered.called, 'registered called before instance created');
+    assert.isFalse(window.XLazy.prototype.registered.called, 'registered called before instance created');
     document.createElement('x-lazy');
-    assert.isTrue(XLazy.prototype.registered.called, 'registered not called after instance created');
+    assert.isTrue(window.XLazy.prototype.registered.called, 'registered not called after instance created');
   });
 
   test('registered called at registration time if `eagerRegister` is true', function() {
-    assert.isTrue(XEager.prototype.registered.called, 'registered not called before instance created');
+    assert.isTrue(window.XEager.prototype.registered.called, 'registered not called before instance created');
     document.createElement('x-eager');
-    assert.isTrue(XLazy.prototype.registered.calledOnce, 'registered called more than once');
+    assert.isTrue(window.XLazy.prototype.registered.calledOnce, 'registered called more than once');
   });
 
   test('styles shimmed at first instance', function() {