Fix serializer not using attrs before extracting attributes

addon/mixin.js

@@ -135,6 +135,8 @@ export default Ember.Mixin.create({
     let data;
 
     if (payload) {
+      this.normalizeUsingDeclaredMapping(primaryModelClass, payload);
+
       const attributes = this.extractAttributes(primaryModelClass, payload),
         relationships = this.extractRelationships(primaryModelClass, payload, included);
 

tests/dummy/app/models/attr.js

@@ -0,0 +1,6 @@
+import DS from 'ember-data';
+
+export default DS.Model.extend({
+  admin: DS.attr('boolean'),
+  occupation: DS.attr('string')
+});

tests/dummy/app/serializers/application.js

@@ -2,6 +2,12 @@ import HalSerializer from "ember-data-hal-9000/serializer";
 import Ember from 'ember';
 
 export default HalSerializer.extend({
+  // example attrs from http://emberjs.com/api/data/classes/DS.JSONAPISerializer.html#property_attrs
+  attrs: {
+    admin: 'is_admin',
+    occupation: { key: 'career' }
+  },
+
   keyForRelationship(key) {
     return Ember.String.underscore(key);
   }

tests/unit/models/attr-test.js

@@ -0,0 +1,31 @@
+import {
+  test,
+  moduleForModel
+} from "ember-qunit";
+import { stubRequest } from 'ember-cli-fake-server';
+import Ember from "ember";
+
+moduleForModel('attr', 'Attributes', {
+  needs: ['serializer:application', 'adapter:application', 'transform:temperature',
+  'model:attribute']
+});
+
+test('uses serializers attrs key', function(assert){
+  assert.expect(2);
+
+  stubRequest('get', '/attrs/1', (request) => {
+    request.ok({
+      id: 1,
+      is_admin: true,
+      career: 'ninja'
+    });
+  });
+
+  const store = this.store();
+  return Ember.run(function(){
+    return store.findRecord('attr', 1).then(function(attr){
+      assert.equal(attr.get('admin'), true);
+      assert.equal(attr.get('occupation'), 'ninja');
+    });
+  });
+});