diff --git a/apps/files/tests/controller/apicontrollertest.php b/apps/files/tests/controller/apicontrollertest.php
index 5d32a693ad30f6e55a303c2a07655e02323db52d..bbab711310c387adccd37f64edf2e3e0db41a984 100644
--- a/apps/files/tests/controller/apicontrollertest.php
+++ b/apps/files/tests/controller/apicontrollertest.php
@@ -110,7 +110,7 @@ class ApiControllerTest extends TestCase {
 				[
 					'id' => null,
 					'parentId' => null,
-					'date' => 'January 1, 1970 at 12:00:55 AM GMT+0',
+					'date' => \OCP\Util::formatDate(55),
 					'mtime' => 55000,
 					'icon' => \OCA\Files\Helper::determineIcon($fileInfo),
 					'name' => 'root.txt',
@@ -175,7 +175,7 @@ class ApiControllerTest extends TestCase {
 				[
 					'id' => null,
 					'parentId' => null,
-					'date' => 'January 1, 1970 at 12:00:55 AM GMT+0',
+					'date' => \OCP\Util::formatDate(55),
 					'mtime' => 55000,
 					'icon' => \OCA\Files\Helper::determineIcon($fileInfo1),
 					'name' => 'root.txt',
@@ -194,7 +194,7 @@ class ApiControllerTest extends TestCase {
 				[
 					'id' => null,
 					'parentId' => null,
-					'date' => 'January 1, 1970 at 12:16:39 AM GMT+0',
+					'date' => \OCP\Util::formatDate(999),
 					'mtime' => 999000,
 					'icon' => \OCA\Files\Helper::determineIcon($fileInfo2),
 					'name' => 'root.txt',
diff --git a/lib/private/datetimezone.php b/lib/private/datetimezone.php
index acc956e66f363c2e2c7c3b00e2a47b787ebd11f9..512c39be3ea49503f4ef3ff32b56f7f07ede22a6 100644
--- a/lib/private/datetimezone.php
+++ b/lib/private/datetimezone.php
@@ -48,13 +48,14 @@ class DateTimeZone implements IDateTimeZone {
 	/**
 	 * Get the timezone of the current user, based on his session information and config data
 	 *
+	 * @param bool|int $timestamp
 	 * @return \DateTimeZone
 	 */
-	public function getTimeZone() {
+	public function getTimeZone($timestamp = false) {
 		$timeZone = $this->config->getUserValue($this->session->get('user_id'), 'core', 'timezone', null);
 		if ($timeZone === null) {
 			if ($this->session->exists('timezone')) {
-				return $this->guessTimeZoneFromOffset($this->session->get('timezone'));
+				return $this->guessTimeZoneFromOffset($this->session->get('timezone'), $timestamp);
 			}
 			$timeZone = $this->getDefaultTimeZone();
 		}
@@ -74,9 +75,10 @@ class DateTimeZone implements IDateTimeZone {
 	 * we try to find it manually, before falling back to UTC.
 	 *
 	 * @param mixed $offset
+	 * @param bool|int $timestamp
 	 * @return \DateTimeZone
 	 */
-	protected function guessTimeZoneFromOffset($offset) {
+	protected function guessTimeZoneFromOffset($offset, $timestamp) {
 		try {
 			// Note: the timeZone name is the inverse to the offset,
 			// so a positive offset means negative timeZone
@@ -93,7 +95,13 @@ class DateTimeZone implements IDateTimeZone {
 			// we try to guess one timezone that has the same offset
 			foreach (\DateTimeZone::listIdentifiers() as $timeZone) {
 				$dtz = new \DateTimeZone($timeZone);
-				$dtOffset = $dtz->getOffset(new \DateTime());
+				$dateTime = new \DateTime();
+
+				if ($timestamp !== false) {
+					$dateTime->setTimestamp($timestamp);
+				}
+
+				$dtOffset = $dtz->getOffset($dateTime);
 				if ($dtOffset == 3600 * $offset) {
 					return $dtz;
 				}
diff --git a/lib/public/idatetimezone.php b/lib/public/idatetimezone.php
index 30fbde15ac84cc520b374f0bed4e2b307acf5229..eb74074aa468eeefece3181d06440a1dd051c314 100644
--- a/lib/public/idatetimezone.php
+++ b/lib/public/idatetimezone.php
@@ -25,7 +25,8 @@ namespace OCP;
 
 interface IDateTimeZone {
 	/**
+	 * @param bool|int $timestamp
 	 * @return \DateTimeZone
 	 */
-	public function getTimeZone();
+	public function getTimeZone($timestamp = false);
 }
diff --git a/tests/lib/util.php b/tests/lib/util.php
index 49399c8cf0183a791b0a53dc021ebe39b6a40df9..e52a9fcc618f087e53b79229e558a310033428ea 100644
--- a/tests/lib/util.php
+++ b/tests/lib/util.php
@@ -54,24 +54,27 @@ class Test_Util extends \Test\TestCase {
 
 	public function formatDateWithTZFromSessionData() {
 		return array(
-			array(3, 'October 13, 2012 at 2:53:25 PM GMT+3'),
-			array(15, 'October 13, 2012 at 11:53:25 AM GMT+0'),
-			array(-13, 'October 13, 2012 at 11:53:25 AM GMT+0'),
-			array(9.5, 'October 13, 2012 at 9:23:25 PM GMT+9:30'),
-			array(-4.5, 'October 13, 2012 at 7:23:25 AM GMT-4:30'),
-			array(15.5, 'October 13, 2012 at 11:53:25 AM GMT+0'),
+			array(3, 'October 13, 2012 at 2:53:25 PM GMT+3', 'Etc/GMT-3'),
+			array(15, 'October 13, 2012 at 11:53:25 AM GMT+0', 'UTC'),
+			array(-13, 'October 13, 2012 at 11:53:25 AM GMT+0', 'UTC'),
+			array(9.5, 'October 13, 2012 at 9:23:25 PM GMT+9:30', 'Australia/Darwin'),
+			array(-4.5, 'October 13, 2012 at 7:23:25 AM GMT-4:30', 'America/Caracas'),
+			array(15.5, 'October 13, 2012 at 11:53:25 AM GMT+0', 'UTC'),
 		);
 	}
 
 	/**
 	 * @dataProvider formatDateWithTZFromSessionData
 	 */
-	function testFormatDateWithTZFromSession($offset, $expected) {
+	function testFormatDateWithTZFromSession($offset, $expected, $expectedTimeZone) {
 		date_default_timezone_set("UTC");
 
 		$oldDateTimeFormatter = \OC::$server->query('DateTimeFormatter');
 		\OC::$server->getSession()->set('timezone', $offset);
-		$newDateTimeFormatter = new \OC\DateTimeFormatter(\OC::$server->getDateTimeZone()->getTimeZone(), new \OC_L10N('lib', 'en'));
+
+		$selectedTimeZone = \OC::$server->getDateTimeZone()->getTimeZone(1350129205);
+		$this->assertEquals($expectedTimeZone, $selectedTimeZone->getName());
+		$newDateTimeFormatter = new \OC\DateTimeFormatter($selectedTimeZone, new \OC_L10N('lib', 'en'));
 		$this->setDateFormatter($newDateTimeFormatter);
 
 		$result = OC_Util::formatDate(1350129205, false);