MAGETWO-58409: Checkout Flow Improvements

- Implement additional checks

Author: Andrei Malets

app/code/Magento/Quote/Model/Quote/Payment.php

@@ -60,6 +60,11 @@ class Payment extends \Magento\Payment\Model\Info implements PaymentInterface
      */
     protected $methodSpecificationFactory;
 
+    /**
+     * @var array
+     */
+    private $additionalChecks;
+
     /**
      * @param \Magento\Framework\Model\Context $context
      * @param \Magento\Framework\Registry $registry
@@ -71,6 +76,7 @@ class Payment extends \Magento\Payment\Model\Info implements PaymentInterface
      * @param \Magento\Framework\Model\ResourceModel\AbstractResource $resource
      * @param \Magento\Framework\Data\Collection\AbstractDb $resourceCollection
      * @param array $data
+     * @param array $additionalChecks
      * @SuppressWarnings(PHPMD.ExcessiveParameterList)
      */
     public function __construct(
@@ -83,9 +89,11 @@ public function __construct(
         \Magento\Payment\Model\Checks\SpecificationFactory $methodSpecificationFactory,
         \Magento\Framework\Model\ResourceModel\AbstractResource $resource = null,
         \Magento\Framework\Data\Collection\AbstractDb $resourceCollection = null,
-        array $data = []
+        array $data = [],
+        array $additionalChecks = []
     ) {
         $this->methodSpecificationFactory = $methodSpecificationFactory;
+        $this->additionalChecks = $additionalChecks;
         parent::__construct(
             $context,
             $registry,
@@ -162,7 +170,8 @@ public function importData(array $data)
          */
         $quote->collectTotals();
 
-        $methodSpecification = $this->methodSpecificationFactory->create($data->getChecks());
+        $checks = array_merge($data->getChecks(), $this->additionalChecks);
+        $methodSpecification = $this->methodSpecificationFactory->create($checks);
         if (!$method->isAvailable($quote) || !$methodSpecification->isApplicable($method, $quote)) {
             throw new \Magento\Framework\Exception\LocalizedException(
                 __('The requested Payment Method is not available.')