Add tests

* When extended, a behavior `registered` is always called on sub-most prototype rather than the prototype on which `registered` was defined.
* behavior property default values are overwritten by later behaviors and elements
* readOnly properties ignored when a previous behavior observes the property
* observedAttributes when extended

test/unit/behaviors.html

@@ -397,6 +397,45 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       zot: 'zot'
     });
 
+    Polymer({
+      is: 'override-default-value',
+      behaviors: [
+        {
+          properties: {
+            foo: { value: true },
+            bar: { value: true}
+          }
+        },
+        {
+          properties: {
+            foo: { value: true },
+            bar: String,
+            zot: {value: true}
+          }
+        },
+
+      ],
+
+      properties: {
+        foo: String,
+        zot: String
+      }
+    });
+
+    Polymer({
+      is: 'property-observer-readonly',
+      behaviors: [
+        {
+          observers: ['_changed(bar)'],
+          _changed() {}
+        }
+      ],
+
+      properties: {
+        bar: {readOnly: true}
+      }
+    });
+
 </script>
 
   <test-fixture id="single">
@@ -471,6 +510,18 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     </template>
   </test-fixture>
 
+  <test-fixture id="override-default-value">
+    <template>
+      <override-default-value></override-default-value>
+    </template>
+  </test-fixture>
+
+  <test-fixture id="property-observer-readonly">
+    <template>
+      <property-observer-readonly></property-observer-readonly>
+    </template>
+  </test-fixture>
+
 <script type="module">
 import { Polymer } from '../../polymer-legacy.js';
 
@@ -534,6 +585,19 @@ suite('single behavior element', function() {
     assert.equal(el.nug, 'nug');
   });
 
+  test('behavior default values can be overridden', function() {
+    const el = fixture('override-default-value');
+    assert.notOk(el.foo);
+    assert.notOk(el.bar);
+    assert.notOk(el.zot);
+  });
+
+  test('readOnly not applied when property was previously observed', function() {
+    const el = fixture('property-observer-readonly');
+    el.bar = 5;
+    assert.equal(el.bar, 5);
+  });
+
 });
 
 suite('behavior.registered', function() {

test/unit/mixin-behaviors.html

@@ -389,6 +389,48 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     customElements.define('before-register-observers', klass);
   </script>
 
+  <script type="module">
+    import { mixinBehaviors } from '../../lib/legacy/class.js';
+    import { PolymerElement } from '../../polymer-element.js';
+
+    const Base = mixinBehaviors([{
+      registered() {
+        this.usedExtendedProto = this.canUseExtendedProto;
+      }
+    }], PolymerElement);
+
+    customElements.define('registered-proto', mixinBehaviors([
+      {canUseExtendedProto: true}
+    ], Base));
+
+  </script>
+
+  <script type="module">
+    import { mixinBehaviors } from '../../lib/legacy/class.js';
+    import { PolymerElement } from '../../polymer-element.js';
+
+
+    class Base extends mixinBehaviors([{
+        properties: {b1: String} }], PolymerElement) {
+
+      static get properties() {
+        return { e1: String};
+      }
+    }
+
+    class El extends mixinBehaviors([{
+        properties: {b2: String}}], Base) {
+
+      static get properties() {
+        return { e2: String};
+      }
+
+    }
+
+    customElements.define('extended-observed-attributes', El);
+
+  </script>
+
   <test-fixture id="single">
     <template>
       <single-behavior></single-behavior>
@@ -436,6 +478,20 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       <behavior-registered-ext></behavior-registered-ext>
     </template>
   </test-fixture>
+
+  <test-fixture id="registered-proto">
+    <template>
+      <registered-proto></registered-proto>
+    </template>
+  </test-fixture>
+
+  <test-fixture id="extended-observed-attributes">
+    <template>
+      <extended-observed-attributes b1="b1" e1="e1" b2="b2" e2="e2"></extended-observed-attributes>
+    </template>
+  </test-fixture>
+
+
 <script type="module">
 import { Polymer } from '../../polymer-legacy.js';
 import { mixinBehaviors } from '../../lib/legacy/class.js';
@@ -508,7 +564,12 @@ suite('behavior.registered/beforeRegister', function() {
     var el = fixture('before-register-observers');
     el.foo = 1;
     assert.equal(el.__fooChangedCalled, 1);
-});
+  });
+
+  test('registered called on class prototype when extended', function() {
+    var el = fixture('registered-proto');
+    assert.isTrue(el.usedExtendedProto);
+  });
 
 });
 
@@ -657,6 +718,14 @@ suite('extended-behaviors', function() {
     assert.deepEqual(el.__createdList, ['1', '2', 'sup', '3', '4', 'sub'], 'created list wrong');
   });
 
+  test('observedAttributes when extended', function() {
+    const el = fixture('extended-observed-attributes');
+    assert.equal(el.b1, 'b1');
+    assert.equal(el.e1, 'e1');
+    assert.equal(el.b2, 'b2');
+    assert.equal(el.e2, 'e2');
+  });
+
 });
 
 </script>