diff --git a/Controller/ApiController.php b/Controller/ApiController.php
index 25274b3..455beff 100644
--- a/Controller/ApiController.php
+++ b/Controller/ApiController.php
@@ -178,7 +178,7 @@ final class ApiController extends Controller
             return;
         }
 
-        /** @var Localization #l11n */
+        /** @var Localization $l11n */
         $l11n = AccountMapper::get($accountId)->getL11n();
 
         if ((bool) ($request->getData('load') ?? false)) {
diff --git a/Models/AccountMapper.php b/Models/AccountMapper.php
index 4a5d3d6..a4794d7 100644
--- a/Models/AccountMapper.php
+++ b/Models/AccountMapper.php
@@ -119,6 +119,9 @@ final class AccountMapper extends DataMapperAbstract
      *
      * @return Account
      *
+     * @todo Orange-Management/oms-Admin#11
+     *  [AccountMapper] Create test for getWithPermission()
+     *
      * @since 1.0.0
      */
     public static function getWithPermissions(int $id) : Account
diff --git a/tests/Controller/Api/ApiControllerSettingsTrait.php b/tests/Controller/Api/ApiControllerSettingsTrait.php
index ddc33a3..f58da82 100644
--- a/tests/Controller/Api/ApiControllerSettingsTrait.php
+++ b/tests/Controller/Api/ApiControllerSettingsTrait.php
@@ -55,4 +55,57 @@ trait ApiControllerSettingsTrait
         $this->module->apiSettingsGet($request, $response);
         self::assertEquals('US', $response->get('')['response']);
     }
+
+    public function testApiAccountLocalizationLoadSet() : void
+    {
+        $response = new HttpResponse();
+        $request  = new HttpRequest(new HttpUri(''));
+
+        $request->getHeader()->setAccount(1);
+        $request->setData('account_id', 1);
+        $request->setData('load', true);
+        $request->setData('localization_load', 'de_DE');
+        $this->module->apiSettingsAccountLocalizationSet($request, $response);
+
+        $l11n = $response->get('')['response'];
+        self::assertEquals($l11n->getLanguage(), 'de');
+
+        $request->setData('localization_load', 'en_US', true);
+        $this->module->apiSettingsAccountLocalizationSet($request, $response);
+
+        $l11n = $response->get('')['response'];
+        self::assertEquals($l11n->getLanguage(), 'en');
+    }
+
+    public function testApiAccountLocalizationSet() : void
+    {
+        $response = new HttpResponse();
+        $request  = new HttpRequest(new HttpUri(''));
+
+        $request->getHeader()->setAccount(1);
+        $request->setData('account_id', 1);
+
+        $data = \json_decode('{"settings_country":"US","settings_language":"en","settings_temperature":"celsius","settings_timezone":"America\/New_York","settings_timeformat_vs":"d.m","settings_timeformat_s":"m.y","settings_timeformat_m":"Y.m.d","settings_timeformat_l":"Y.m.d h:i","settings_timeformat_vl":"Y.m.d h:i:s","settings_currency":"EUR","settings_currencyformat":"0","settings_decimal":".","settings_thousands":",","settings_precision_vs":"0","settings_precision_s":"1","settings_precision_m":"2","settings_precision_l":"3","settings_precision_vl":"5","settings_weight_vl":"mg","settings_weight_l":"g","settings_weight_m":"kg","settings_weight_h":"t","settings_weight_vh":"t","settings_speed_vs":"mps","settings_speed_s":"ms","settings_speed_m":"kph","settings_speed_f":"kph","settings_speed_vf":"mach","settings_speed_sea":"mpd","settings_length_vs":"micron","settings_length_s":"mm","settings_length_m":"cm","settings_length_l":"m","settings_length_vl":"km","settings_length_sea":"mi","settings_area_vs":"micron","settings_area_s":"mm","settings_area_m":"cm","settings_area_l":"m","settings_area_vl":"km","settings_volume_vs":"mul","settings_volume_s":"ml","settings_volume_m":"l","settings_volume_l":"cm","settings_volume_vl":"m","settings_volume_teaspoon":"Metric tsp","settings_volume_tablespoon":"Metric tblsp","settings_volume_glass":"Metric cup"}', true);
+
+        foreach ($data as $key => $value) {
+            $request->setData($key, $value);
+        }
+
+        $this->module->apiSettingsAccountLocalizationSet($request, $response);
+
+        $l11n = $response->get('')['response'];
+        self::assertEquals($l11n->getCurrency(), 'EUR');
+    }
+
+    public function testInvalidPermissionAccountLocalizationSet() : void
+    {
+        $response = new HttpResponse();
+        $request  = new HttpRequest(new HttpUri(''));
+
+        $request->getHeader()->setAccount(2);
+        $request->setData('account_id', 1);
+        $this->module->apiSettingsAccountLocalizationSet($request, $response);
+
+        self::assertEquals([], $response->get('')['response']);
+    }
 }
diff --git a/tests/Models/NullAccountPermissionTest.php b/tests/Models/NullAccountPermissionTest.php
new file mode 100644
index 0000000..ede80c1
--- /dev/null
+++ b/tests/Models/NullAccountPermissionTest.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace Modules\Admin\tests\Models;
+
+use Modules\Admin\Models\NullAccountPermission;
+
+/**
+ * @internal
+ */
+final class NullAccountPermissionTest extends \PHPUnit\Framework\TestCase
+{
+    public function testNull() : void
+    {
+        self::assertInstanceOf('\Modules\Admin\Models\AccountPermission', new NullAccountPermission());
+    }
+
+    public function testId() : void
+    {
+        $null = new NullAccountPermission(2);
+        self::assertEquals(2, $null->getId());
+    }
+}
diff --git a/tests/Models/NullAccountTest.php b/tests/Models/NullAccountTest.php
new file mode 100644
index 0000000..7d7d757
--- /dev/null
+++ b/tests/Models/NullAccountTest.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace Modules\Admin\tests\Models;
+
+use Modules\Admin\Models\NullAccount;
+
+/**
+ * @internal
+ */
+final class NullAccountTest extends \PHPUnit\Framework\TestCase
+{
+    public function testNull() : void
+    {
+        self::assertInstanceOf('\Modules\Admin\Models\Account', new NullAccount());
+    }
+
+    public function testId() : void
+    {
+        $null = new NullAccount(2);
+        self::assertEquals(2, $null->getId());
+    }
+}
diff --git a/tests/Models/NullAddressTest.php b/tests/Models/NullAddressTest.php
new file mode 100644
index 0000000..1f48ecf
--- /dev/null
+++ b/tests/Models/NullAddressTest.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace Modules\Admin\tests\Models;
+
+use Modules\Admin\Models\NullAddress;
+
+/**
+ * @internal
+ */
+final class NullAddressTest extends \PHPUnit\Framework\TestCase
+{
+    public function testNull() : void
+    {
+        self::assertInstanceOf('\Modules\Admin\Models\Address', new NullAddress());
+    }
+
+    public function testId() : void
+    {
+        $null = new NullAddress(2);
+        self::assertEquals(2, $null->getId());
+    }
+}
diff --git a/tests/Models/NullGroupPermissionTest.php b/tests/Models/NullGroupPermissionTest.php
new file mode 100644
index 0000000..64b3fbf
--- /dev/null
+++ b/tests/Models/NullGroupPermissionTest.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace Modules\Admin\tests\Models;
+
+use Modules\Admin\Models\NullGroupPermission;
+
+/**
+ * @internal
+ */
+final class NullGroupPermissionTest extends \PHPUnit\Framework\TestCase
+{
+    public function testNull() : void
+    {
+        self::assertInstanceOf('\Modules\Admin\Models\GroupPermission', new NullGroupPermission());
+    }
+
+    public function testId() : void
+    {
+        $null = new NullGroupPermission(2);
+        self::assertEquals(2, $null->getId());
+    }
+}
diff --git a/tests/Models/NullGroupTest.php b/tests/Models/NullGroupTest.php
new file mode 100644
index 0000000..bacbd2b
--- /dev/null
+++ b/tests/Models/NullGroupTest.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace Modules\Admin\tests\Models;
+
+use Modules\Admin\Models\NullGroup;
+
+/**
+ * @internal
+ */
+final class NullGroupTest extends \PHPUnit\Framework\TestCase
+{
+    public function testNull() : void
+    {
+        self::assertInstanceOf('\Modules\Admin\Models\Group', new NullGroup());
+    }
+
+    public function testId() : void
+    {
+        $null = new NullGroup(2);
+        self::assertEquals(2, $null->getId());
+    }
+}