diff --git a/tests/Result/Item/ParticipantTest.php b/tests/Result/Item/ParticipantTest.php
index 952894a..6ba08b1 100644
--- a/tests/Result/Item/ParticipantTest.php
+++ b/tests/Result/Item/ParticipantTest.php
@@ -14,6 +14,7 @@ use Meritoo\Common\Type\OopVisibilityType;
 use Meritoo\LimeSurvey\ApiClient\Result\Item\Participant;
 use Meritoo\LimeSurvey\ApiClient\Result\Processor\ResultProcessor;
 use Meritoo\LimeSurvey\ApiClient\Type\MethodType;
+use Meritoo\LimeSurvey\Test\ApiClient\Utilities\DateUtility;
 
 /**
  * Test case of the one item of the result/data: full data of participant
@@ -196,7 +197,7 @@ class ParticipantTest extends BaseTestCase
                 'completed'      => 'N',
                 'usesleft'       => 10,
                 'validfrom'      => null,
-                'validuntil'     => (new DateTime())->format('Y-m-d H:i:s'),
+                'validuntil'     => DateUtility::getDateTime(),
             ],
             [
                 'tid'            => '456',
@@ -212,9 +213,9 @@ class ParticipantTest extends BaseTestCase
                 'sent'           => 'Y',
                 'remindersent'   => 'N',
                 'remindercount'  => 1,
-                'completed'      => (new DateTime())->format('Y-m-d H:i'),
+                'completed'      => DateUtility::getDateTime(false),
                 'usesleft'       => 5,
-                'validfrom'      => (new DateTime())->format('Y-m-d H:i:s'),
+                'validfrom'      => DateUtility::getDateTime(),
                 'validuntil'     => null,
             ],
         ];
diff --git a/tests/Result/Item/SurveyTest.php b/tests/Result/Item/SurveyTest.php
index 638cac9..6fd7243 100644
--- a/tests/Result/Item/SurveyTest.php
+++ b/tests/Result/Item/SurveyTest.php
@@ -14,6 +14,7 @@ use Meritoo\Common\Type\OopVisibilityType;
 use Meritoo\LimeSurvey\ApiClient\Result\Item\Survey;
 use Meritoo\LimeSurvey\ApiClient\Result\Processor\ResultProcessor;
 use Meritoo\LimeSurvey\ApiClient\Type\MethodType;
+use Meritoo\LimeSurvey\Test\ApiClient\Utilities\DateUtility;
 
 /**
  * Test case of the one item of the result/data: survey
@@ -99,13 +100,13 @@ class SurveyTest extends BaseTestCase
                 'sid'            => '123',
                 'surveyls_title' => 'Test',
                 'startdate'      => null,
-                'expires'        => (new DateTime())->format('Y-m-d H:i:s'),
+                'expires'        => DateUtility::getDateTime(),
                 'active'         => 'N',
             ],
             [
                 'sid'            => '456',
                 'surveyls_title' => 'Another Test',
-                'startdate'      => (new DateTime())->format('Y-m-d H:i:s'),
+                'startdate'      => DateUtility::getDateTime(),
                 'expires'        => null,
                 'active'         => 'Y',
             ],
diff --git a/tests/Result/ResultTest.php b/tests/Result/ResultTest.php
index 5ccc906..4520826 100644
--- a/tests/Result/ResultTest.php
+++ b/tests/Result/ResultTest.php
@@ -8,13 +8,13 @@
 
 namespace Meritoo\LimeSurvey\Test\ApiClient\Result\Result;
 
-use DateTime;
 use Meritoo\Common\Test\Base\BaseTestCase;
 use Meritoo\Common\Type\OopVisibilityType;
 use Meritoo\LimeSurvey\ApiClient\Base\Result\BaseItem;
 use Meritoo\LimeSurvey\ApiClient\Exception\CannotProcessDataException;
 use Meritoo\LimeSurvey\ApiClient\Result\Result;
 use Meritoo\LimeSurvey\ApiClient\Type\MethodType;
+use Meritoo\LimeSurvey\Test\ApiClient\Utilities\DateUtility;
 use PHPUnit_Framework_MockObject_MockObject;
 
 /**
@@ -179,7 +179,7 @@ class ResultTest extends BaseTestCase
             [
                 'sid'            => '456',
                 'surveyls_title' => 'Another Test',
-                'startdate'      => (new DateTime())->format('Y-m-d H:i:s'),
+                'startdate'      => DateUtility::getDateTime(),
                 'expires'        => null,
                 'active'         => 'Y',
             ],
diff --git a/tests/Service/ParticipantServiceTest.php b/tests/Service/ParticipantServiceTest.php
index d57e010..19e7a8d 100644
--- a/tests/Service/ParticipantServiceTest.php
+++ b/tests/Service/ParticipantServiceTest.php
@@ -8,7 +8,6 @@
 
 namespace Meritoo\LimeSurvey\Test\ApiClient\Service;
 
-use DateTime;
 use Exception;
 use Meritoo\Common\Collection\Collection;
 use Meritoo\Common\Test\Base\BaseTestCase;
@@ -23,6 +22,7 @@ use Meritoo\LimeSurvey\ApiClient\Result\Collection\ParticipantsDetails;
 use Meritoo\LimeSurvey\ApiClient\Result\Item\Participant;
 use Meritoo\LimeSurvey\ApiClient\Service\ParticipantService;
 use Meritoo\LimeSurvey\ApiClient\Type\ReasonType;
+use Meritoo\LimeSurvey\Test\ApiClient\Utilities\DateUtility;
 use PHPUnit_Framework_MockObject_MockObject;
 
 /**
@@ -209,10 +209,10 @@ class ParticipantServiceTest extends BaseTestCase
                 'sent'           => 'Y',
                 'remindersent'   => 'N',
                 'remindercount'  => 0,
-                'completed'      => (new DateTime())->format('Y-m-d H:i:s'),
+                'completed'      => DateUtility::getDateTime(),
                 'usesleft'       => 10,
                 'validfrom'      => null,
-                'validuntil'     => (new DateTime())->format('Y-m-d H:i:s'),
+                'validuntil'     => DateUtility::getDateTime(),
             ],
             [
                 'tid'            => 2,
@@ -231,7 +231,7 @@ class ParticipantServiceTest extends BaseTestCase
                 'completed'      => 'N',
                 'usesleft'       => 10,
                 'validfrom'      => null,
-                'validuntil'     => (new DateTime())->format('Y-m-d H:i:s'),
+                'validuntil'     => DateUtility::getDateTime(),
             ],
         ];
     }
diff --git a/tests/Utilities/DateUtility.php b/tests/Utilities/DateUtility.php
new file mode 100644
index 0000000..7941ed7
--- /dev/null
+++ b/tests/Utilities/DateUtility.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * (c) Meritoo.pl, http://www.meritoo.pl
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Meritoo\LimeSurvey\Test\ApiClient\Utilities;
+
+use DateTime;
+
+/**
+ * Date-related utility
+ *
+ * @author    Krzysztof Niziol <krzysztof.niziol@meritoo.pl>
+ * @copyright Meritoo.pl
+ */
+class DateUtility
+{
+    /**
+     * Returns date formatted with long or medium format
+     *
+     * @param bool $useLongFormat (optional) If is set to true, long format will be used (default behaviour).
+     *                            Otherwise - medium format.
+     * @return string
+     */
+    public static function getDateTime($useLongFormat = true)
+    {
+        $format = 'Y-m-d H:i';
+
+        if ($useLongFormat) {
+            $format = 'Y-m-d H:i:s';
+        }
+
+        return (new DateTime())->format($format);
+    }
+}