MAGETWO-72466: [Backport][2.1.x] PayPal.js error on checkout downloadable product

Author: OlgaVasyltsun

dev/tests/functional/tests/app/Magento/Checkout/Test/Block/Onepage/Login.php

@@ -49,6 +49,8 @@ class Login extends Form
      */
     protected $loadingMask = '.loading-mask';
 
+    private $emailSelector = '[name="username"]';
+
     /**
      * Select how to perform checkout whether guest or registered customer.
      *
@@ -98,8 +100,7 @@ public function loginCustomer(FixtureInterface $customer)
      */
     public function fillGuestFields(FixtureInterface $customer)
     {
-        $mapping = $this->dataMapping();
-        $this->_rootElement->find($mapping['email']['selector'], $mapping['email']['strategy'])
+        $this->_rootElement->find($this->emailSelector)
             ->setValue($customer->getEmail());
     }
 

dev/tests/functional/tests/app/Magento/Checkout/Test/TestStep/SelectCheckoutMethodStep.php

@@ -82,10 +82,8 @@ public function run()
     {
         if ($this->checkoutMethod === 'login') {
             $this->checkoutOnepage->getLoginBlock()->loginCustomer($this->customer);
-        } elseif ($this->checkoutMethod === 'guest') {
-            if (empty($this->shipping)) {
-                $this->checkoutOnepage->getLoginBlock()->fillGuestFields($this->customer);
-            }
+        } elseif (($this->checkoutMethod === 'guest') && empty($this->shipping)) {
+            $this->checkoutOnepage->getLoginBlock()->fillGuestFields($this->customer);
         }
     }