Small adjustments

Author: eduard13

app/code/Magento/Checkout/Test/Unit/Plugin/ResetQuoteAddressesTest.php

@@ -31,6 +31,11 @@ class ResetQuoteAddressesTest extends TestCase
      */
     private const STUB_ITEM_ID = 1;
 
+    /**
+     * @var int
+     */
+    private const STUB_SHIPPING_ASSIGNMENTS = 1;
+
     /**
      * @var array
      */
@@ -133,7 +138,7 @@ public function testClearingAddressesSuccessfullyFromEmptyQuoteWithAddress(
         if (!$isVirtualQuote && $extensionAttributes) {
             $this->extensionAttributesMock->expects($this->any())
                 ->method('getShippingAssignments')
-                ->willReturn($extensionAttributes);
+                ->willReturn([static::STUB_SHIPPING_ASSIGNMENTS]);
 
             $this->extensionAttributesMock->expects($this->once())
                 ->method('setShippingAssignments')