MAGETWO-59649: Current store resolver does not work for global scope

Author: le0n4eg

app/code/Magento/Store/Model/StoreManager.php

@@ -152,7 +152,7 @@ public function isSingleStoreMode()
     public function getStore($storeId = null)
     {
         if (!isset($storeId) || '' === $storeId || $storeId === true) {
-            if (!$this->currentStoreId) {
+            if (null === $this->currentStoreId) {
                 \Magento\Framework\Profiler::start('store.resolve');
                 $this->currentStoreId = $this->storeResolver->getCurrentStoreId();
                 \Magento\Framework\Profiler::stop('store.resolve');

dev/tests/integration/testsuite/Magento/Store/Model/StoreManagerTest.php

@@ -0,0 +1,48 @@
+<?php
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Store\Model;
+
+use Magento\Framework\ObjectManagerInterface as ObjectManager;
+use Magento\Store\Model\Store;
+use Magento\Store\Model\StoreManagerInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+
+class StoreManagerTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var StoreManagerInterface
+     */
+    private $storeManager;
+
+    /**
+     * @var ObjectManager
+     */
+    private $objectManager;
+
+    /**
+     * Class dependencies initialization
+     *
+     * @return void
+     */
+    protected function setUp()
+    {
+        $this->objectManager = Bootstrap::getObjectManager();
+        $this->storeManager = $this->objectManager->get(StoreManagerInterface::class);
+    }
+
+    /**
+     * Check that behavior of setting and getting store into StoreManager is correct
+     * Setting: Magento\Store\Model\StoreManagerInterface::setCurrentStore
+     * Getting: Magento\Store\Model\StoreManagerInterface::getStore
+     *
+     * @return void
+     */
+    public function testDefaultStoreIdIsSetCorrectly()
+    {
+        $this->storeManager->setCurrentStore(Store::DEFAULT_STORE_ID);
+        $this->assertEquals(Store::DEFAULT_STORE_ID, $this->storeManager->getStore()->getId());
+    }
+}