diff --git a/apps/dav/lib/hookmanager.php b/apps/dav/lib/hookmanager.php
index 4a4704ff2a..687e6718db 100644
--- a/apps/dav/lib/hookmanager.php
+++ b/apps/dav/lib/hookmanager.php
@@ -100,26 +100,26 @@ class HookManager {
 
 	public function postLogin($params) {
 		$user = $this->userManager->get($params['uid']);
-
-		$principal = 'principals/users/' . $user->getUID();
-		$calendars = $this->calDav->getCalendarsForUser($principal);
-		if (empty($calendars)) {
-			try {
-				$this->calDav->createCalendar($principal, 'personal', [
-					'displayname' => 'Personal']);
-			} catch (\Exception $ex) {
-				\OC::$server->getLogger()->logException($ex);
+		if (!is_null($user)) {
+			$principal = 'principals/users/' . $user->getUID();
+			$calendars = $this->calDav->getCalendarsForUser($principal);
+			if (empty($calendars)) {
+				try {
+					$this->calDav->createCalendar($principal, 'personal', [
+						'{DAV:}displayname' => 'Personal']);
+				} catch (\Exception $ex) {
+					\OC::$server->getLogger()->logException($ex);
+				}
+			}
+			$books = $this->cardDav->getAddressBooksForUser($principal);
+			if (empty($books)) {
+				try {
+					$this->cardDav->createAddressBook($principal, 'contacts', [
+						'{DAV:}displayname' => 'Contacts']);
+				} catch (\Exception $ex) {
+					\OC::$server->getLogger()->logException($ex);
+				}
 			}
 		}
-		$books = $this->cardDav->getAddressBooksForUser($principal);
-		if (empty($books)) {
-			try {
-				$this->cardDav->createAddressBook($principal, 'contacts', [
-					'displayname' => 'Contacts']);
-			} catch (\Exception $ex) {
-				\OC::$server->getLogger()->logException($ex);
-			}
-		}
-
 	}
 }
diff --git a/apps/dav/tests/unit/dav/HookManagerTest.php b/apps/dav/tests/unit/dav/HookManagerTest.php
new file mode 100644
index 0000000000..bec4c240ce
--- /dev/null
+++ b/apps/dav/tests/unit/dav/HookManagerTest.php
@@ -0,0 +1,71 @@
+<?php
+
+/**
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\DAV\Tests\Unit\DAV;
+
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCA\DAV\CardDAV\CardDavBackend;
+use OCA\DAV\CardDAV\SyncService;
+use OCA\DAV\HookManager;
+use OCP\IUserManager;
+use Test\TestCase;
+
+class HookManagerTest extends TestCase {
+	public function test() {
+		$user = $this->getMockBuilder('\OCP\IUser')
+			->disableOriginalConstructor()
+			->getMock();
+		$user->expects($this->once())->method('getUID')->willReturn('newUser');
+
+		/** @var IUserManager | \PHPUnit_Framework_MockObject_MockObject $userManager */
+		$userManager = $this->getMockBuilder('\OCP\IUserManager')
+			->disableOriginalConstructor()
+			->getMock();
+		$userManager->expects($this->once())->method('get')->willReturn($user);
+
+		/** @var SyncService | \PHPUnit_Framework_MockObject_MockObject $syncService */
+		$syncService = $this->getMockBuilder('OCA\DAV\CardDAV\SyncService')
+			->disableOriginalConstructor()
+			->getMock();
+
+		/** @var CalDavBackend | \PHPUnit_Framework_MockObject_MockObject $cal */
+		$cal = $this->getMockBuilder('OCA\DAV\CalDAV\CalDavBackend')
+			->disableOriginalConstructor()
+			->getMock();
+		$cal->expects($this->once())->method('getCalendarsForUser')->willReturn([]);
+		$cal->expects($this->once())->method('createCalendar')->with(
+			'principals/users/newUser',
+			'personal', ['{DAV:}displayname' => 'Personal']);
+
+		/** @var CardDavBackend | \PHPUnit_Framework_MockObject_MockObject $card */
+		$card = $this->getMockBuilder('OCA\DAV\CardDAV\CardDavBackend')
+			->disableOriginalConstructor()
+			->getMock();
+		$card->expects($this->once())->method('getAddressBooksForUser')->willReturn([]);
+		$card->expects($this->once())->method('createAddressBook')->with(
+			'principals/users/newUser',
+			'contacts', ['{DAV:}displayname' => 'Contacts']);
+
+		$hm = new HookManager($userManager, $syncService, $cal, $card);
+		$hm->postLogin(['uid' => 'newUser']);
+	}
+}