MAGETWO-69856: [Backport] - [Github] Wrong error message in cart after entering invalid discount code #7230 - for 2.1

Author: DianaRusin

app/code/Magento/Checkout/Controller/Cart/CouponPost.php

@@ -7,6 +7,8 @@
 
 /**
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ *
+ * Coupon Post controller.
  */
 class CouponPost extends \Magento\Checkout\Controller\Cart
 {

app/code/Magento/Checkout/Test/Unit/Controller/Cart/CouponPostTest.php

@@ -8,9 +8,9 @@
 use Magento\Checkout\Controller\Cart\Index;
 
 /**
- * Class IndexTest
- *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ *
+ * Test for \Magento\Checkout\Controller\Cart\CouponPost
  */
 class CouponPostTest extends \PHPUnit_Framework_TestCase
 {

dev/tests/integration/testsuite/Magento/ConfigurableProduct/_files/configurable_attribute.php

@@ -18,7 +18,7 @@
 
     /** @var $attribute \Magento\Catalog\Model\ResourceModel\Eav\Attribute */
     $attribute = Bootstrap::getObjectManager()->create(
-        'Magento\Catalog\Model\ResourceModel\Eav\Attribute'
+        \Magento\Catalog\Model\ResourceModel\Eav\Attribute::class
     );
 
     /** @var AttributeRepositoryInterface $attributeRepository */

dev/tests/integration/testsuite/Magento/ConfigurableProduct/_files/quote_with_configurable_product_last_variation.php

@@ -8,6 +8,8 @@
 
 require __DIR__ . '/configurable_products.php';
 
+$objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+
 /** @var \Magento\Quote\Model\Quote $quote */
 $quote = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(\Magento\Quote\Model\Quote::class);
 
@@ -55,14 +57,10 @@
     );
 
 /** @var \Magento\Quote\Model\QuoteRepository $quoteRepository */
-$quoteRepository = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(
-    \Magento\Quote\Model\QuoteRepository::class
-);
+$quoteRepository = $objectManager->create(\Magento\Quote\Model\QuoteRepository::class);
 $quote->collectTotals();
 $quoteRepository->save($quote);
 
 /** @var \Magento\Checkout\Model\Session $session */
-$session = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(
-    \Magento\Checkout\Model\Session::class
-);
+$session = $objectManager->create(\Magento\Checkout\Model\Session::class);
 $session->setQuoteId($quote->getId());