Merge remote-tracking branch 'remotes/github/MAGETWO-95821' into EPAM-PR-23

Author: VeronikaYarats

app/code/Magento/Paypal/Controller/Express/AbstractExpress.php

@@ -7,12 +7,17 @@
 
 use Magento\Checkout\Controller\Express\RedirectLoginInterface;
 use Magento\Framework\App\Action\Action as AppAction;
+use Magento\Framework\App\Action\HttpGetActionInterface;
+use Magento\Framework\App\Action\HttpPostActionInterface;
 
 /**
  * Abstract Express Checkout Controller
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
-abstract class AbstractExpress extends AppAction implements RedirectLoginInterface
+abstract class AbstractExpress extends AppAction implements
+    RedirectLoginInterface,
+    HttpGetActionInterface,
+    HttpPostActionInterface
 {
     /**
      * @var \Magento\Paypal\Model\Express\Checkout
@@ -137,6 +142,14 @@ protected function _initCheckout()
             $this->getResponse()->setStatusHeader(403, '1.1', 'Forbidden');
             throw new \Magento\Framework\Exception\LocalizedException(__('We can\'t initialize Express Checkout.'));
         }
+        if (!(float)$quote->getGrandTotal()) {
+            throw new \Magento\Framework\Exception\LocalizedException(
+                __(
+                    'PayPal can\'t process orders with a zero balance due. '
+                    . 'To finish your purchase, please go through the standard checkout process.'
+                )
+            );
+        }
         if (!isset($this->_checkoutTypes[$this->_checkoutType])) {
             $parameters = [
                 'params' => [
@@ -151,6 +164,8 @@ protected function _initCheckout()
     }
 
     /**
+     * Get Proper Checkout Token
+     *
      * Search for proper checkout token in request or session or (un)set specified one
      * Combined getter/setter
      *
@@ -221,17 +236,15 @@ protected function _getQuote()
     }
 
     /**
-     * Returns before_auth_url redirect parameter for customer session
-     * @return null
+     * @inheritdoc
      */
     public function getCustomerBeforeAuthUrl()
     {
         return;
     }
 
     /**
-     * Returns a list of action flags [flag_key] => boolean
-     * @return array
+     * @inheritdoc
      */
     public function getActionFlagList()
     {
@@ -240,6 +253,7 @@ public function getActionFlagList()
 
     /**
      * Returns login url parameter for redirect
+     *
      * @return string
      */
     public function getLoginUrl()
@@ -249,6 +263,7 @@ public function getLoginUrl()
 
     /**
      * Returns action name which requires redirect
+     *
      * @return string
      */
     public function getRedirectActionName()
@@ -269,4 +284,9 @@ public function redirectLogin()
             $this->_urlHelper->addRequestParam($this->_customerUrl->getLoginUrl(), ['context' => 'checkout'])
         );
     }
+
+    /**
+     * @inheritdoc
+     */
+    abstract public function execute();
 }