MC-21481: TransportBuilder doesn't add "to" email-addresses, if given in array

Author: Roman Lytvynenko

dev/tests/integration/framework/Magento/TestFramework/Mail/Template/TransportBuilderMock.php

@@ -38,11 +38,12 @@ public function getSentMessage()
      * Return transport mock.
      *
      * @return \Magento\TestFramework\Mail\TransportInterfaceMock
+     * @throws \Magento\Framework\Exception\LocalizedException
      */
     public function getTransport()
     {
         $this->prepareMessage();
         $this->reset();
-        return new \Magento\TestFramework\Mail\TransportInterfaceMock();
+        return new \Magento\TestFramework\Mail\TransportInterfaceMock($this->message);
     }
 }

dev/tests/integration/framework/Magento/TestFramework/Mail/TransportInterfaceMock.php

@@ -8,6 +8,13 @@
 
 class TransportInterfaceMock implements \Magento\Framework\Mail\TransportInterface
 {
+    private $message;
+
+    public function __construct($message = '')
+    {
+        $this->message = $message;
+    }
+
     /**
      * Mock of send a mail using transport
      *
@@ -21,10 +28,10 @@ public function sendMessage()
     /**
      * Get message
      *
-     * @return string
+     * @return mixed
      */
     public function getMessage()
     {
-        return '';
+        return $this->message;
     }
 }

dev/tests/integration/testsuite/Magento/Email/Model/_files/email_template.php

@@ -10,9 +10,9 @@
 $template->setOptions(['area' => 'test area', 'store' => 1]);
 $template->setData(
     [
-        'template_text' =>
-            file_get_contents(__DIR__ . '/template_fixture.html'),
-        'template_code' => \Magento\Theme\Model\Config\ValidatorTest::TEMPLATE_CODE
+        'template_text' => file_get_contents(__DIR__ . '/template_fixture.html'),
+        'template_code' => \Magento\Theme\Model\Config\ValidatorTest::TEMPLATE_CODE,
+        'template_type' => \Magento\Email\Model\Template::TYPE_TEXT
     ]
 );
 $template->save();

dev/tests/integration/testsuite/Magento/Framework/Mail/TransportBuilderTest.php

@@ -0,0 +1,100 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Framework\Mail;
+
+use Magento\Email\Model\BackendTemplate;
+use Magento\Email\Model\Template;
+use Magento\Framework\Mail\Template\TransportBuilder;
+use Magento\Framework\ObjectManagerInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Class EmailMessageTest
+ */
+class TransportBuilderTest extends TestCase
+{
+    /**
+     * @var ObjectManagerInterface
+     */
+    private $di;
+
+    /**
+     * @var TransportBuilder
+     */
+    protected $builder;
+
+    /**
+     * @var Template
+     */
+    protected $template;
+
+    protected function setUp()
+    {
+        $this->di = Bootstrap::getObjectManager();
+        $this->builder = $this->di->get(TransportBuilder::class);
+        $this->template = $this->di->get(Template::class);
+    }
+
+    /**
+     * @magentoDataFixture Magento/Email/Model/_files/email_template.php
+     * @magentoDbIsolation enabled
+     *
+     * @param string|array $email
+     * @dataProvider emailDataProvider
+     * @throws \Magento\Framework\Exception\LocalizedException
+     */
+    public function testAddToEmail($email)
+    {
+        $templateId = $this->template->load('email_exception_fixture', 'template_code')->getId();
+
+        $this->builder->setTemplateModel(BackendTemplate::class);
+
+        $vars = ['reason' => 'Reason', 'customer' => 'Customer'];
+        $options = ['area' => 'frontend', 'store' => 1];
+        $this->builder->setTemplateIdentifier($templateId)->setTemplateVars($vars)->setTemplateOptions($options);
+
+        $this->builder->addTo($email);
+
+        /** @var EmailMessage $emailMessage */
+        $emailMessage = $this->builder->getTransport();
+
+        $addresses = $emailMessage->getMessage()->getTo();
+
+        $emails = [];
+        /** @var Address $toAddress */
+        foreach ($addresses as $address) {
+            $emails[] = $address->getEmail();
+        }
+
+        if (is_string($email)) {
+            $this->assertCount(1, $emails);
+            $this->assertEquals($email, $emails[0]);
+        } else {
+            $this->assertEquals($email, $emails);
+        }
+    }
+
+    /**
+     * @return array
+     */
+    public function emailDataProvider(): array
+    {
+        return [
+            [
+                'billy.everything@someserver.com',
+            ],
+            [
+                [
+                    'billy.everything@someserver.com',
+                    'john.doe@someserver.com',
+                ]
+            ]
+        ];
+    }
+}