logging-in in order to checkout when guest checkout is disabled #6015

app/code/Magento/Checkout/Test/Mftf/Test/StorefrontCustomerCheckoutOnLoginWhenGuestCheckoutIsDisabledTest.xml

@@ -60,7 +60,6 @@
             <argument name="customerEmail" value="$$createCustomer.email$$"/>
             <argument name="customerPwd" value="$$createCustomer.password$$"/>
         </actionGroup>
-        <click selector="{{CheckoutCartSummarySection.proceedToCheckout}}" stepKey="goToCheckout1"/>
         <waitForPageLoad stepKey="waitForShippingMethodSectionToLoad"/>
         <waitForElementVisible selector="{{CheckoutShippingMethodsSection.next}}" stepKey="waitForNextButton"/>
         <click selector="{{CheckoutShippingMethodsSection.next}}" stepKey="clickOnNextButton"/>

app/code/Magento/Checkout/view/frontend/web/js/proceed-to-checkout.js

@@ -18,6 +18,8 @@ define([
             event.preventDefault();
 
             if (!customer().firstname && cart().isGuestCheckoutAllowed === false) {
+                // set URL for redirect on successful login/registration. It's postprocessed on backend.
+                $.cookie('login_redirect', config.checkoutUrl);
                 authenticationPopup.showModal();
 
                 return false;

app/code/Magento/Customer/Controller/Account/CreatePost.php

@@ -363,6 +363,8 @@ public function execute()
         }
         $this->session->regenerateId();
         try {
+            /** Clear redirect cookie to prevent redirect to other pages*/
+            $this->accountRedirect->clearRedirectCookie();
             $address = $this->extractAddress();
             $addresses = $address === null ? [] : [$address];
             $customer = $this->customerExtractor->extract('customer_account_create', $this->_request);