diff --git a/Models/AuditMapper.php b/Models/AuditMapper.php
index 452154e..deb3010 100755
--- a/Models/AuditMapper.php
+++ b/Models/AuditMapper.php
@@ -16,6 +16,7 @@ namespace Modules\Auditor\Models;
 
 use Modules\Admin\Models\AccountMapper;
 use phpOMS\DataStorage\Database\DataMapperAbstract;
+use phpOMS\DataStorage\Database\RelationType;
 
 /**
  * Mapper class.
@@ -91,4 +92,28 @@ final class AuditMapper extends DataMapperAbstract
      * @since 1.0.0
      */
     protected static string $createdAt = 'auditor_audit_created_at';
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function delete($obj, int $relations = RelationType::REFERENCE)
+    {
+        return -1;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function update($obj, int $relations = RelationType::ALL, int $depth = 3)
+    {
+        return -1;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function updateArray(array &$obj, int $relations = RelationType::ALL, int $depth = 1)
+    {
+        return -1;
+    }
 }
diff --git a/tests/Models/AuditMapperTest.php b/tests/Models/AuditMapperTest.php
new file mode 100644
index 0000000..949d57a
--- /dev/null
+++ b/tests/Models/AuditMapperTest.php
@@ -0,0 +1,52 @@
+<?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\Auditor\tests\Models;
+
+use Modules\Auditor\Models\Audit;
+use Modules\Auditor\Models\AuditMapper;
+
+/**
+ * @internal
+ */
+class AuditMapperTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @covers Modules\Auditor\Models\AuditMapper
+     * @group module
+     */
+    public function testInvalidDelete() : void
+    {
+        self::assertEquals(-1, AuditMapper::delete(null));
+    }
+
+    /**
+     * @covers Modules\Auditor\Models\AuditMapper
+     * @group module
+     */
+    public function testInvalidUpdate() : void
+    {
+        self::assertEquals(-1, AuditMapper::update(null));
+    }
+
+    /**
+     * @covers Modules\Auditor\Models\AuditMapper
+     * @group module
+     */
+    public function testInvalidUpdateArray() : void
+    {
+        $arr = [];
+        self::assertEquals(-1, AuditMapper::updateArray($arr));
+    }
+}
diff --git a/tests/Models/NullAuditTest.php b/tests/Models/NullAuditTest.php
new file mode 100644
index 0000000..54afd91
--- /dev/null
+++ b/tests/Models/NullAuditTest.php
@@ -0,0 +1,32 @@
+<?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\Auditor\tests\Models;
+
+use Modules\Auditor\Models\NullAudit;
+
+/**
+ * @internal
+ */
+final class NullAuditTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @covers Modules\Auditor\Models\NullAudit
+     * @group module
+     */
+    public function testNull() : void
+    {
+        self::assertInstanceOf('\Modules\Auditor\Models\Audit', new NullAudit());
+    }
+}