diff --git a/src/Application/Model/MessageTypes/AbstractMessage.php b/src/Application/Model/MessageTypes/AbstractMessage.php
index 4c496fb..06a96c8 100644
--- a/src/Application/Model/MessageTypes/AbstractMessage.php
+++ b/src/Application/Model/MessageTypes/AbstractMessage.php
@@ -15,7 +15,6 @@ declare(strict_types=1);
 
 namespace D3\Linkmobility4OXID\Application\Model\MessageTypes;
 
-use D3\LinkmobilityClient\RecipientsList\RecipientsList;
 use D3\LinkmobilityClient\RecipientsList\RecipientsListInterface;
 use D3\LinkmobilityClient\Response\ResponseInterface;
 use D3\LinkmobilityClient\ValueObject\Recipient;
diff --git a/src/tests/integration/LMIntegrationTestCase.php b/src/tests/integration/LMIntegrationTestCase.php
new file mode 100644
index 0000000..7a12402
--- /dev/null
+++ b/src/tests/integration/LMIntegrationTestCase.php
@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * This Software is the property of Data Development and is protected
+ * by copyright law - it is NOT Freeware.
+ * Any unauthorized use of this software without a valid license
+ * is a violation of the license agreement and will be prosecuted by
+ * civil and criminal law.
+ * http://www.shopmodule.com
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author        D3 Data Development - Daniel Seifert <support@shopmodule.com>
+ * @link          http://www.oxidmodule.com
+ */
+
+namespace D3\Linkmobility4OXID\tests\integration;
+
+use D3\Linkmobility4OXID\Application\Model\MessageClient;
+use D3\Linkmobility4OXID\tests\unit\LMUnitTestCase;
+use D3\LinkmobilityClient\Client;
+use Doctrine\DBAL\Exception;
+use Doctrine\DBAL\Query\QueryBuilder;
+use GuzzleHttp\Client as GuzzleClient;
+use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use OxidEsales\Eshop\Application\Model\Remark;
+use OxidEsales\EshopCommunity\Internal\Container\ContainerFactory;
+use OxidEsales\EshopCommunity\Internal\Framework\Database\QueryBuilderFactoryInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\NotFoundExceptionInterface;
+use Psr\Http\Message\ResponseInterface;
+
+abstract class LMIntegrationTestCase extends LMUnitTestCase
+{
+    /**
+     * @param $userId
+     *
+     * @throws Exception
+     * @throws ContainerExceptionInterface
+     * @throws NotFoundExceptionInterface
+     */
+    protected function deleteAllRemarksFrom($userId)
+    {
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->delete(oxNew(Remark::class)->getCoreTableName())
+        ->where(
+            $queryBuilder->expr()->eq(
+                'oxparentid',
+                $queryBuilder->createNamedParameter($userId)
+            )
+        );
+        $queryBuilder->execute();
+    }
+
+    /**
+     * @param ResponseInterface|RequestException $response
+     */
+    protected function setClientResponse($response, callable $history = null)
+    {
+        $handlerMock = new MockHandler([$response]);
+
+        $handlerStack = HandlerStack::create($handlerMock);
+
+        if ($history) {
+            $handlerStack->push($history);
+        }
+
+        $guzzleMock = new GuzzleClient(['handler' => $handlerStack]);
+
+        /** @var Client $LMClient */
+        $LMClient = oxNew(Client::class, 'accessToken', null, $guzzleMock);
+
+        /** @var MessageClient|MockObject $messageClientMock */
+        $messageClientMock = $this->getMockBuilder(MessageClient::class)
+            ->onlyMethods(['getClient'])
+            ->getMock();
+        $messageClientMock->method('getClient')->willReturn($LMClient);
+
+        d3GetOxidDIC()->set(MessageClient::class, $messageClientMock);
+    }
+}
\ No newline at end of file
diff --git a/src/tests/integration/adminOrderTest.php b/src/tests/integration/adminOrderTest.php
new file mode 100644
index 0000000..596d82d
--- /dev/null
+++ b/src/tests/integration/adminOrderTest.php
@@ -0,0 +1,418 @@
+<?php
+
+/**
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <support@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\Linkmobility4OXID\tests\integration;
+
+use D3\Linkmobility4OXID\Application\Controller\Admin\AdminOrder;
+use D3\Linkmobility4OXID\Application\Model\Configuration;
+use Doctrine\DBAL\Query\QueryBuilder;
+use Exception;
+use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Middleware;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use OxidEsales\Eshop\Application\Model\Order;
+use OxidEsales\Eshop\Application\Model\Remark;
+use OxidEsales\Eshop\Application\Model\User;
+use OxidEsales\Eshop\Core\Registry;
+use OxidEsales\EshopCommunity\Internal\Container\ContainerFactory;
+use OxidEsales\EshopCommunity\Internal\Framework\Database\QueryBuilderFactoryInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Http\Message\RequestInterface;
+
+class adminOrderTest extends LMIntegrationTestCase
+{
+    /** @var Order */
+    protected $order;
+    protected $userId = 'testUserId';
+    protected $orderId = 'testOrderId';
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        /** @var Configuration|MockObject $configuration */
+        $configuration = $this->getMockBuilder(Configuration::class)
+            ->onlyMethods(['getTestMode'])
+            ->getMock();
+        $configuration->method('getTestMode')->willReturn(true);
+        d3GetOxidDIC()->set(Configuration::class, $configuration);
+
+        /** @var User $order */
+        $this->order = $order = oxNew( Order::class);
+        $order->setId($this->orderId);
+        $order->assign([
+            'oxbillfon'         => '01512 3456789',
+            'oxbillcountryid'   => 'a7c40f631fc920687.20179984',
+            'oxuserid'          => $this->userId
+        ]);
+        $order->save();
+
+        /** @var User $user */
+        $this->user = $user = oxNew(User::class);
+        $user->setId($this->userId);
+        $user->save();
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function succSending()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                ['X-Foo' => 'Bar'],
+                '{"statusCode":2000,"statusMessage":"OK","clientMessageId":null,"transferId":"0063c11b0100eeda5a1d","smsCount":1}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->orderId;
+
+        /** @var AdminOrder $controller */
+        $controller = oxNew(AdminOrder::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            1,
+            $container
+        );
+        /** @var RequestInterface $request */
+        $request = $container[0]['request'];
+        $this->assertTrue(
+            (bool) strpos(serialize($request->getBody()->getContents()), 'testMessage')
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_SMS_SUCC_SENT'),
+            1
+        );
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+            ->from(oxNew(Remark::class)->getViewName())
+            ->where(
+                $queryBuilder->expr()->eq(
+                    'oxparentid',
+                    $queryBuilder->createNamedParameter($this->userId)
+                )
+            );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) > 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function apiError()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                [],
+                '{"statusCode": 4019, "statusMessage": "parameter \"messageContent\" invalid", "clientMessageId": null, "transferId": null, "smsCount": 0}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->orderId;
+
+        /** @var AdminOrder $controller */
+        $controller = oxNew(AdminOrder::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            1,
+            $container
+        );
+        /** @var RequestInterface $request */
+        $request = $container[0]['request'];
+        $this->assertTrue(
+            (bool) strpos(serialize($request->getBody()->getContents()), 'testMessage')
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_UNEXPECTED_ERR_SEND'),
+            'parameter "messageContent" invalid'
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function emptyMessage()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                [],
+                '{"statusCode": 4019, "statusMessage": "parameter \"messageContent\" invalid", "clientMessageId": null, "transferId": null, "smsCount": 0}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = '';
+        $_POST['oxid'] = $this->orderId;
+
+        /** @var AdminOrder $controller */
+        $controller = oxNew(AdminOrder::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            0,  // no request because of internal handling
+            $container
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_NO_LENGTH'),
+            1
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function recipientError()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                ['X-Foo' => 'Bar'],
+                '{"statusCode":2000,"statusMessage":"OK","clientMessageId":null,"transferId":"0063c11b0100eeda5a1d","smsCount":1}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->orderId;
+
+        $this->order->assign( [
+            'oxbillfon' => '',
+            'oxbillcountryid'   => ''
+        ]);
+        $this->order->save();
+
+        /** @var AdminOrder $controller */
+        $controller = oxNew(AdminOrder::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            0,  // no request because of internal handling
+            $container
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_UNEXPECTED_ERR_SEND'),
+            'no response'
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function communicationError()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new RequestException(
+                'Error Communicating with Server',
+                new Request('GET', 'test')
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->orderId;
+
+        /** @var AdminOrder $controller */
+        $controller = oxNew(AdminOrder::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            1,
+            $container
+        );
+        /** @var RequestInterface $request */
+        $request = $container[0]['request'];
+        $this->assertTrue(
+            (bool) strpos(serialize($request->getBody()->getContents()), 'testMessage')
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_UNEXPECTED_ERR_SEND'),
+            'no response'
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @throws Exception
+     */
+    public function tearDown(): void
+    {
+        parent::tearDown();
+
+        $this->order->delete();
+        $this->user->delete();
+    }
+}
\ No newline at end of file
diff --git a/src/tests/integration/adminUserTest.php b/src/tests/integration/adminUserTest.php
new file mode 100644
index 0000000..4b7e64e
--- /dev/null
+++ b/src/tests/integration/adminUserTest.php
@@ -0,0 +1,409 @@
+<?php
+
+/**
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <support@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\Linkmobility4OXID\tests\integration;
+
+use D3\Linkmobility4OXID\Application\Model\Configuration;
+use \D3\Linkmobility4OXID\Application\Controller\Admin\AdminUser;
+use Doctrine\DBAL\Query\QueryBuilder;
+use Exception;
+use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Middleware;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use OxidEsales\Eshop\Application\Model\Remark;
+use OxidEsales\Eshop\Application\Model\User;
+use OxidEsales\Eshop\Core\Registry;
+use OxidEsales\EshopCommunity\Internal\Container\ContainerFactory;
+use OxidEsales\EshopCommunity\Internal\Framework\Database\QueryBuilderFactoryInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Http\Message\RequestInterface;
+
+class adminUserTest extends LMIntegrationTestCase
+{
+    /** @var User */
+    protected $user;
+    protected $userId = 'testUserId';
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        /** @var Configuration|MockObject $configuration */
+        $configuration = $this->getMockBuilder(Configuration::class)
+            ->onlyMethods(['getTestMode'])
+            ->getMock();
+        $configuration->method('getTestMode')->willReturn(true);
+        d3GetOxidDIC()->set(Configuration::class, $configuration);
+
+        /** @var User $user */
+        $this->user = $user = oxNew(User::class);
+        $user->setId($this->userId);
+        $user->assign([
+            'oxfon' => '01512 3456789',
+            'oxcountryid'   => 'a7c40f631fc920687.20179984'
+        ]);
+        $user->save();
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function succSending()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                ['X-Foo' => 'Bar'],
+                '{"statusCode":2000,"statusMessage":"OK","clientMessageId":null,"transferId":"0063c11b0100eeda5a1d","smsCount":1}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->userId;
+
+        /** @var AdminUser $controller */
+        $controller = oxNew(AdminUser::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            1,
+            $container
+        );
+        /** @var RequestInterface $request */
+        $request = $container[0]['request'];
+        $this->assertTrue(
+            (bool) strpos(serialize($request->getBody()->getContents()), 'testMessage')
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_SMS_SUCC_SENT'),
+            1
+        );
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+            ->from(oxNew(Remark::class)->getViewName())
+            ->where(
+                $queryBuilder->expr()->eq(
+                    'oxparentid',
+                    $queryBuilder->createNamedParameter($this->userId)
+                )
+            );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) > 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function apiError()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                [],
+                '{"statusCode": 4019, "statusMessage": "parameter \"messageContent\" invalid", "clientMessageId": null, "transferId": null, "smsCount": 0}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->userId;
+
+        /** @var AdminUser $controller */
+        $controller = oxNew(AdminUser::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            1,
+            $container
+        );
+        /** @var RequestInterface $request */
+        $request = $container[0]['request'];
+        $this->assertTrue(
+            (bool) strpos(serialize($request->getBody()->getContents()), 'testMessage')
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_UNEXPECTED_ERR_SEND'),
+            'parameter "messageContent" invalid'
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function emptyMessage()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                [],
+                '{"statusCode": 4019, "statusMessage": "parameter \"messageContent\" invalid", "clientMessageId": null, "transferId": null, "smsCount": 0}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = '';
+        $_POST['oxid'] = $this->userId;
+
+        /** @var AdminUser $controller */
+        $controller = oxNew(AdminUser::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            0,  // no request because of internal handling
+            $container
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_NO_LENGTH'),
+            1
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function recipientError()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new Response(
+                200,
+                ['X-Foo' => 'Bar'],
+                '{"statusCode":2000,"statusMessage":"OK","clientMessageId":null,"transferId":"0063c11b0100eeda5a1d","smsCount":1}'
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->userId;
+
+        $this->user->assign([
+            'oxfon' => '',
+            'oxcountryid'   => ''
+        ]);
+        $this->user->save();
+
+        /** @var AdminUser $controller */
+        $controller = oxNew(AdminUser::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            0,  // no request because of internal handling
+            $container
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_UNEXPECTED_ERR_SEND'),
+            'no response'
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @test
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Psr\Container\ContainerExceptionInterface
+     * @throws \Psr\Container\NotFoundExceptionInterface
+     */
+    public function communicationError()
+    {
+        $container  =  [];
+        $history  =  Middleware::history($container);
+
+        $this->deleteAllRemarksFrom($this->userId);
+
+        $this->setClientResponse(
+            new RequestException(
+                'Error Communicating with Server',
+                new Request('GET', 'test')
+            ),
+            $history
+        );
+
+        $_POST['messagebody'] = 'testMessage';
+        $_POST['oxid'] = $this->userId;
+
+        /** @var AdminUser $controller */
+        $controller = oxNew(AdminUser::class);
+        $controller->send();
+
+        // check requests
+        $this->assertCount(
+            1,
+            $container
+        );
+        /** @var RequestInterface $request */
+        $request = $container[0]['request'];
+        $this->assertTrue(
+            (bool) strpos(serialize($request->getBody()->getContents()), 'testMessage')
+        );
+
+        // check return message
+        $search = sprintf(
+            Registry::getLang()->translateString('D3LM_EXC_MESSAGE_UNEXPECTED_ERR_SEND'),
+            'no response'
+        );
+
+        $this->assertTrue(
+            (bool) strpos(serialize(Registry::getSession()->getVariable('Errors')), $search)
+        );
+
+        // check remark
+        /** @var QueryBuilder $queryBuilder */
+        $queryBuilder = ContainerFactory::getInstance()->getContainer()->get(QueryBuilderFactoryInterface::class)->create();
+        $queryBuilder->select('oxid')
+                     ->from(oxNew(Remark::class)->getViewName())
+                     ->where(
+                         $queryBuilder->expr()->eq(
+                             'oxparentid',
+                             $queryBuilder->createNamedParameter($this->userId)
+                         )
+                     );
+        $remarkIds = $queryBuilder->execute()->fetchAll();
+        $this->assertTrue(
+            count($remarkIds) == 0
+        );
+
+        $this->deleteAllRemarksFrom($this->userId);
+    }
+
+    /**
+     * @throws Exception
+     */
+    public function tearDown(): void
+    {
+        parent::tearDown();
+
+        $this->user->delete();
+    }
+}
\ No newline at end of file