perQty如果为空，则用minPackQty，兼容测试环境

components/store/CommodityInfo.vue

@@ -88,7 +88,7 @@
                  <span>{{(calculate || 0)}}</span>
               </span>
             </div>
-            <div class="button" ng-controller="GoodsPickUpCtrl">
+            <div class="button">
               <button class="btn btn-default btn-primary" @click="buyNow(false, commodity)">加入购物车</button>
               <button class="btn btn-default btn-now" @click="buyNow(true, commodity)">立即购买</button>
             </div>
@@ -214,7 +214,7 @@ export default {
       }
     },
     changeNum: function (newNum) {
-      let pack = this.commodity.perQty
+      let pack = this.commodity.perQty || this.commodity.minPackQty
       let buy = this.commodity.minBuyQty
       let reserve = this.commodity.reserve
       if (newNum < buy) {
@@ -258,12 +258,14 @@ export default {
       }
     },
     subNum () {
-      let newNum = this.fragment.num - this.commodity.perQty
+      let pack = this.commodity.perQty || this.commodity.minPackQty
+      let newNum = this.fragment.num - pack
       this.changeNum(newNum)
       getFragment(this.commodity, this.fragment)
     },
     addNum () {
-      let newNum = this.fragment.num + this.commodity.perQty
+      let pack = this.commodity.perQty || this.commodity.minPackQty
+      let newNum = this.fragment.num + pack
       this.changeNum(newNum)
       getFragment(this.commodity, this.fragment)
     },