diff --git a/Classes/DataProcessing/CopyToProcessor.php b/Classes/DataProcessing/CopyToProcessor.php
index e9eb8cf..a0b41de 100644
--- a/Classes/DataProcessing/CopyToProcessor.php
+++ b/Classes/DataProcessing/CopyToProcessor.php
@@ -20,18 +20,30 @@ namespace Codappix\SearchCore\DataProcessing;
  * 02110-1301, USA.
  */
 
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
 /**
  * Copies values from one field to another one.
  */
 class CopyToProcessor implements ProcessorInterface
 {
+    /**
+     * @var array
+     */
+    protected $keysToCopy = [];
+
     public function processRecord(array $record, array $configuration)
     {
-        $all = [];
+        $result = [];
+        $this->keysToCopy = array_keys($record);
 
-        $this->addArray($all, $record);
-        $all = array_filter($all);
-        $record[$configuration['to']] = implode(PHP_EOL, $all);
+        if (isset($configuration['from'])) {
+            $this->keysToCopy = GeneralUtility::trimExplode(',', $configuration['from']);
+        }
+
+        $this->addArray($result, $record);
+        $result = array_filter($result);
+        $record[$configuration['to']] = implode(PHP_EOL, $result);
 
         return $record;
     }
@@ -43,6 +55,9 @@ class CopyToProcessor implements ProcessorInterface
     protected function addArray(array &$to, array $from)
     {
         foreach ($from as $property => $value) {
+            if (!in_array($property, $this->keysToCopy)) {
+                continue;
+            }
             if (is_array($value)) {
                 $this->addArray($to, $value);
                 continue;
diff --git a/Tests/Unit/DataProcessing/CopyToProcessorTest.php b/Tests/Unit/DataProcessing/CopyToProcessorTest.php
new file mode 100644
index 0000000..67c60f4
--- /dev/null
+++ b/Tests/Unit/DataProcessing/CopyToProcessorTest.php
@@ -0,0 +1,113 @@
+<?php
+namespace Codappix\SearchCore\Tests\Unit\DataProcessing;
+
+/*
+ * Copyright (C) 2017  Daniel Siepmann <coding@daniel-siepmann.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use Codappix\SearchCore\DataProcessing\CopyToProcessor;
+use Codappix\SearchCore\Tests\Unit\AbstractUnitTestCase;
+
+class CopyToProcessorTest extends AbstractUnitTestCase
+{
+    /**
+     * @param array $record
+     * @param array $configuration
+     * @param array $expectedRecord
+     *
+     * @test
+     * @dataProvider getTestData
+     */
+    public function recordIsReturnedExpectedtoProvidedConfiguration(array $record, array $configuration, array $expectedRecord)
+    {
+        $processor = new CopyToProcessor();
+
+        $this->assertSame(
+            $expectedRecord,
+            $processor->processRecord($record, $configuration),
+            ''
+        );
+    }
+
+    public function getTestData()
+    {
+        return [
+            'copy all' => [
+                'record' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                ],
+                'configuration' => [
+                    'to' => 'new field',
+                ],
+                'expectedRecord' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                    'new field' => "Some content\nAnother content",
+                ],
+            ],
+            'copy one' => [
+                'record' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                ],
+                'configuration' => [
+                    'from' => 'field_1',
+                    'to' => 'new field',
+                ],
+                'expectedRecord' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                    'new field' => 'Some content',
+                ],
+            ],
+            'copy some' => [
+                'record' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                    'field_3' => 'Another one',
+                ],
+                'configuration' => [
+                    'from' => 'field_1, field_3',
+                    'to' => 'new field',
+                ],
+                'expectedRecord' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                    'field_3' => 'Another one',
+                    'new field' => "Some content\nAnother one",
+                ],
+            ],
+            'configure to copy non existing fields' => [
+                'record' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                ],
+                'configuration' => [
+                    'from' => 'non_existing, field_1',
+                    'to' => 'new field',
+                ],
+                'expectedRecord' => [
+                    'field_1' => 'Some content',
+                    'field_2' => 'Another content',
+                    'new field' => 'Some content',
+                ],
+            ],
+        ];
+    }
+}