Fix getReservedOrderId() to use current store instead of default store

app/code/Magento/Quote/Model/ResourceModel/Quote.php

@@ -167,7 +167,7 @@ public function getReservedOrderId($quote)
     {
         return $this->sequenceManager->getSequence(
             \Magento\Sales\Model\Order::ENTITY,
-            $quote->getStore()->getGroup()->getDefaultStoreId()
+            $quote->getStoreId()
         )
         ->getNextValue();
     }
@@ -211,7 +211,7 @@ public function markQuotesRecollectOnCatalogRules()
      * @param \Magento\Catalog\Model\Product $product
      * @return $this
      */
-    public function substractProductFromQuotes($product)
+    public function subtractProductFromQuotes($product)
     {
         $productId = (int)$product->getId();
         if (!$productId) {
@@ -251,6 +251,21 @@ public function substractProductFromQuotes($product)
         return $this;
     }
 
+    /**
+     * Subtract product from all quotes quantities
+     *
+     * @param \Magento\Catalog\Model\Product $product
+     *
+     * @deprecated 101.0.1
+     * @see \Magento\Quote\Model\ResourceModel\Quote::subtractProductFromQuotes
+     *
+     * @return $this
+     */
+    public function substractProductFromQuotes($product)
+    {
+        return $this->subtractProductFromQuotes($product);
+    }
+
     /**
      * Mark recollect contain product(s) quotes
      *

app/code/Magento/Quote/Test/Unit/Model/ResourceModel/QuoteTest.php

@@ -0,0 +1,103 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\Quote\Test\Unit\Model\ResourceModel;
+
+use Magento\Framework\DB\Sequence\SequenceInterface;
+use Magento\Framework\Model\ResourceModel\Db\Context;
+use Magento\Framework\Model\ResourceModel\Db\VersionControl\RelationComposite;
+use Magento\Framework\Model\ResourceModel\Db\VersionControl\Snapshot;
+use Magento\Quote\Model\Quote;
+use Magento\SalesSequence\Model\Manager;
+
+class QuoteTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var Quote|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $quoteMock;
+
+    /**
+     * @var Manager|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $sequenceManagerMock;
+
+    /**
+     * @var SequenceInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $sequenceMock;
+
+    /**
+     * @var \Magento\Quote\Model\ResourceModel\Quote
+     */
+    private $quote;
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function setUp()
+    {
+        $context = $this->getMockBuilder(Context::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $snapshot = $this->getMockBuilder(Snapshot::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $relationComposite = $this->getMockBuilder(RelationComposite::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $this->quoteMock = $this->getMockBuilder(Quote::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $this->sequenceManagerMock = $this->getMockBuilder(Manager::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $this->sequenceMock = $this->getMockBuilder(SequenceInterface::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $this->quote = new \Magento\Quote\Model\ResourceModel\Quote(
+            $context,
+            $snapshot,
+            $relationComposite,
+            $this->sequenceManagerMock,
+            null
+        );
+    }
+
+    /**
+     * @param $entityType
+     * @param $storeId
+     * @param $reservedOrderId
+     * @dataProvider getReservedOrderIdDataProvider
+     */
+    public function testGetReservedOrderId($entityType, $storeId, $reservedOrderId)
+    {
+        $this->sequenceManagerMock->expects($this->once())
+            ->method('getSequence')
+            ->with($entityType, $storeId)
+            ->willReturn($this->sequenceMock);
+        $this->quoteMock->expects($this->once())
+            ->method('getStoreId')
+            ->willReturn($storeId);
+        $this->sequenceMock->expects($this->once())
+            ->method('getNextValue')
+            ->willReturn($reservedOrderId);
+
+        $this->assertEquals($reservedOrderId, $this->quote->getReservedOrderId($this->quoteMock));
+    }
+
+    /**
+     * @return array
+     */
+    public function getReservedOrderIdDataProvider(): array
+    {
+        return [
+            [\Magento\Sales\Model\Order::ENTITY, 1, '1000000001'],
+            [\Magento\Sales\Model\Order::ENTITY, 2, '2000000001'],
+            [\Magento\Sales\Model\Order::ENTITY, 3, '3000000001']
+        ];
+    }
+}

app/code/Magento/Sales/Observer/Backend/SubtractQtyFromQuotesObserver.php

@@ -31,6 +31,6 @@ public function __construct(\Magento\Quote\Model\ResourceModel\Quote $quote)
     public function execute(\Magento\Framework\Event\Observer $observer)
     {
         $product = $observer->getEvent()->getProduct();
-        $this->_quote->substractProductFromQuotes($product);
+        $this->_quote->subtractProductFromQuotes($product);
     }
 }

app/code/Magento/Sales/Test/Unit/Observer/Backend/SubtractQtyFromQuotesObserverTest.php

@@ -15,12 +15,12 @@ class SubtractQtyFromQuotesObserverTest extends \PHPUnit\Framework\TestCase
     protected $_model;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var \Magento\Quote\Model\ResourceModel\Quote|\PHPUnit_Framework_MockObject_MockObject
      */
     protected $_quoteMock;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var \Magento\Framework\Event\Observer|\PHPUnit_Framework_MockObject_MockObject
      */
     protected $_observerMock;
 
@@ -48,7 +48,7 @@ public function testSubtractQtyFromQuotes()
             ['getId', 'getStatus', '__wakeup']
         );
         $this->_eventMock->expects($this->once())->method('getProduct')->will($this->returnValue($productMock));
-        $this->_quoteMock->expects($this->once())->method('substractProductFromQuotes')->with($productMock);
+        $this->_quoteMock->expects($this->once())->method('subtractProductFromQuotes')->with($productMock);
         $this->_model->execute($this->_observerMock);
     }
 }