ENGCOM-3234: Added Unit Test for WindowsSmtpConfig Plugin #18694

 - Merge Pull Request #18694 from vasilii-b/magento2:2.3-WindowsSmtpConfigTest
 - Merged commits:
   1. 1872979

Author: magento-engcom-team

app/code/Magento/Email/Test/Unit/Model/Plugin/WindowsSmtpConfigTest.php

@@ -0,0 +1,100 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Email\Test\Unit\Model\Plugin;
+
+use Magento\Email\Model\Plugin\WindowsSmtpConfig;
+use Magento\Framework\App\Config\ReinitableConfigInterface;
+use Magento\Framework\Mail\TransportInterface;
+use Magento\Framework\OsInfo;
+use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
+
+/**
+ *  WindowsSmtpConfigTest
+ */
+class WindowsSmtpConfigTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var WindowsSmtpConfig
+     */
+    private $windowsSmtpConfig;
+
+    /**
+     * @var OsInfo|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $osInfoMock;
+
+    /**
+     * @var ReinitableConfigInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $configMock;
+
+    /**
+     * @var TransportInterface
+     */
+    private $transportMock;
+
+    /**
+     * setUp
+     *
+     * @return void
+     */
+    public function setUp(): void
+    {
+        $objectManager = new ObjectManager($this);
+
+        $this->osInfoMock = $this->createMock(OsInfo::class);
+        $this->configMock = $this->createMock(ReinitableConfigInterface::class);
+        $this->transportMock = $this->createMock(TransportInterface::class);
+
+        $this->windowsSmtpConfig = $objectManager->getObject(
+            WindowsSmtpConfig::class,
+            [
+                'config' => $this->configMock,
+                'osInfo' => $this->osInfoMock
+            ]
+        );
+    }
+
+    /**
+     * Test if SMTP settings if windows server
+     *
+     * @return void
+     */
+    public function testBeforeSendMessageOsWindows(): void
+    {
+        $this->osInfoMock->expects($this->once())
+            ->method('isWindows')
+            ->willReturn(true);
+
+        $this->configMock->expects($this->exactly(2))
+            ->method('getValue')
+            ->willReturnMap([
+                [WindowsSmtpConfig::XML_SMTP_HOST, '127.0.0.1'],
+                [WindowsSmtpConfig::XML_SMTP_PORT, '80']
+            ]);
+
+        $this->windowsSmtpConfig->beforeSendMessage($this->transportMock);
+    }
+
+    /**
+     * Test if SMTP settings if not windows server
+     *
+     * @return void
+     */
+    public function testBeforeSendMessageOsIsWindows(): void
+    {
+        $this->osInfoMock->expects($this->once())
+            ->method('isWindows')
+            ->willReturn(false);
+
+        $this->configMock->expects($this->never())
+            ->method('getValue');
+
+        $this->windowsSmtpConfig->beforeSendMessage($this->transportMock);
+    }
+}