MC-16371: [FT] CheckoutWithBraintreePaypalMinicartTest fails on Bamboo

Author: svitja

dev/tests/functional/tests/app/Magento/Checkout/Test/Block/Cart/Sidebar.php

@@ -34,7 +34,7 @@ class Sidebar extends Block
      *
      * @var string
      */
-    protected $braintreePaypalCheckoutButton = './/button[contains(@id, "braintree-paypal-mini-cart")]';
+    protected $braintreePaypalCheckoutButton = 'button[id^="braintree-paypal-mini-cart"]';
 
     /**
      * Locator value for "Proceed to Checkout" button.
@@ -124,8 +124,16 @@ public function openMiniCart()
      */
     public function clickBraintreePaypalButton()
     {
-        $this->_rootElement->find($this->braintreePaypalCheckoutButton, Locator::SELECTOR_XPATH)
+        // Button can be enabled/disabled few times.
+        sleep(3);
+
+        $windowsCount = count($this->browser->getWindowHandles());
+        $this->_rootElement->find($this->braintreePaypalCheckoutButton)
             ->click();
+        $browser = $this->browser;
+        $this->browser->waitUntil(function () use ($browser, $windowsCount) {
+            return count($browser->getWindowHandles()) === ($windowsCount + 1) ? true: null;
+        });
     }
 
     /**