diff --git a/lib/Chat/AutoComplete/SearchPlugin.php b/lib/Chat/AutoComplete/SearchPlugin.php
index a380771ab..976fc4468 100644
--- a/lib/Chat/AutoComplete/SearchPlugin.php
+++ b/lib/Chat/AutoComplete/SearchPlugin.php
@@ -37,14 +37,14 @@ class SearchPlugin implements ISearchPlugin {
 	/** @var string */
 	protected $userId;
 
+	/** @var Room */
+	protected $room;
+
 	public function __construct(IUserManager $userManager, $userId) {
 		$this->userManager = $userManager;
 		$this->userId = $userId;
 	}
 
-	/** @var Room */
-	protected $room;
-
 	public function setContext(array $context) {
 		$this->room = $context['room'];
 	}
@@ -117,11 +117,13 @@ class SearchPlugin implements ISearchPlugin {
 	 * @param string $name
 	 * @return array
 	 */
-	public function createResult($type, $uid, $name) {
+	protected function createResult($type, $uid, $name) {
 		if ($type === 'user' && $name === '') {
 			$user = $this->userManager->get($uid);
 			if ($user instanceof IUser) {
 				$name = $user->getDisplayName();
+			} else {
+				$name = $uid;
 			}
 		}
 
diff --git a/tests/php/Chat/AutoComplete/SearchPluginTest.php b/tests/php/Chat/AutoComplete/SearchPluginTest.php
new file mode 100644
index 000000000..d0a89f41d
--- /dev/null
+++ b/tests/php/Chat/AutoComplete/SearchPluginTest.php
@@ -0,0 +1,185 @@
+<?php
+/**
+ * @copyright Copyright (c) 2018 Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Spreed\Tests\php\Chat;
+
+use OCA\Spreed\Chat\AutoComplete\SearchPlugin;
+use OCA\Spreed\Room;
+use OCP\Collaboration\Collaborators\ISearchResult;
+use OCP\IUser;
+use OCP\IUserManager;
+
+class SearchPluginTest extends \Test\TestCase {
+
+	/** @var IUserManager|\PHPUnit_Framework_MockObject_MockObject */
+	protected $userManager;
+
+	/** @var string */
+	protected $userId;
+
+	/** @var SearchPlugin */
+	protected $plugin;
+
+	public function setUp() {
+		parent::setUp();
+
+		$this->userManager = $this->createMock(IUserManager::class);
+		$this->userId = 'current';
+	}
+
+	/**
+	 * @param string[] $methods
+	 * @return SearchPlugin|\PHPUnit_Framework_MockObject_MockObject
+	 */
+	protected function getPlugin(array $methods = []) {
+		if (empty($methods)) {
+			return new SearchPlugin(
+				$this->userManager,
+				$this->userId
+			);
+		}
+
+		return $this->getMockBuilder(SearchPlugin::class)
+			->setConstructorArgs([
+				$this->userManager,
+				$this->userId,
+			])
+			->setMethods($methods)
+			->getMock();
+	}
+
+	public function testSearch() {
+		$result = $this->createMock(ISearchResult::class);
+		$room = $this->createMock(Room::class);
+
+		$room->expects($this->once())
+			->method('getParticipants')
+			->willReturn(['users' => [123 => [], 'foo' => [], 'bar' => []]]);
+
+		$plugin = $this->getPlugin(['searchUsers']);
+		$plugin->setContext(['room' => $room]);
+		$plugin->expects($this->once())
+			->method('searchUsers')
+			->with('fo', ['123', 'foo', 'bar'], $result)
+			->willReturnCallback(function($search, $users, $result) {
+				array_map(function($user) {
+					$this->assertInternalType('string', $user);
+				}, $users);
+			});
+
+		$plugin->search('fo', 10, 0, $result);
+	}
+
+	public function dataSearchUsers() {
+		return [
+			['test', [], [], [], []],
+			['test', ['current', 'foo', 'test', 'test1'], [
+				['uid' => 'current', 'name' => 'test'],
+				['uid' => 'test', 'name' => 'Te st'],
+				['uid' => 'test1', 'name' => 'Te st 1'],
+			], [['test1' => '']], [['test' => '']]],
+			['test', ['foo', 'bar'], [
+				['uid' => 'foo', 'name' => 'Test'],
+				['uid' => 'bar', 'name' => 'test One'],
+			], [['bar' => 'test One']], [['foo' => 'Test']]],
+			['', ['foo', 'bar'], [
+			], [['foo' => ''], ['bar' => '']], []],
+		];
+	}
+
+	/**
+	 * @dataProvider dataSearchUsers
+	 * @param string $search
+	 * @param string[] $userIds
+	 * @param array $userNames
+	 * @param array $expected
+	 * @param array $expectedExact
+	 */
+	public function testSearchUsers($search, array $userIds, array $userNames, array $expected, array $expectedExact) {
+		$result = $this->createMock(ISearchResult::class);
+
+		$userMap = array_map(function($userData) {
+			return [$userData['uid'], $this->createUserMock($userData)];
+		}, $userNames);
+
+		$this->userManager->expects($this->any())
+			->method('get')
+			->willReturnMap($userMap);
+
+		$result->expects($this->once())
+			->method('addResultSet')
+			->with($this->anything(), $expected, $expectedExact);
+
+		$plugin = $this->getPlugin(['createResult']);
+		$plugin->expects($this->any())
+			->method('createResult')
+			->willReturnCallback(function($type, $uid, $name) {
+				return [$uid => $name];
+			});
+
+		self::invokePrivate($plugin, 'searchUsers', [$search, $userIds, $result]);
+	}
+
+	protected function createUserMock(array $userData) {
+		$user = $this->createMock(IUser::class);
+		$user->expects($this->any())
+			->method('getUID')
+			->willReturn($userData['uid']);
+		$user->expects($this->any())
+			->method('getDisplayName')
+			->willReturn($userData['name']);
+		return $user;
+	}
+
+	public function dataCreateResult() {
+		return [
+			['user', 'foo', 'bar', '', ['label' => 'bar', 'value' => ['shareType' => 'user', 'shareWith' => 'foo']]],
+			['user', 'test', 'Test', '', ['label' => 'Test', 'value' => ['shareType' => 'user', 'shareWith' => 'test']]],
+			['user', 'test', '', 'Test', ['label' => 'Test', 'value' => ['shareType' => 'user', 'shareWith' => 'test']]],
+			['user', 'test', '', null, ['label' => 'test', 'value' => ['shareType' => 'user', 'shareWith' => 'test']]],
+		];
+	}
+
+	/**
+	 * @dataProvider dataCreateResult
+	 * @param string $type
+	 * @param string $uid
+	 * @param string $name
+	 * @param string $managerName
+	 * @param array $expected
+	 */
+	public function testCreateResult($type, $uid, $name, $managerName, array $expected) {
+		if ($managerName !== null) {
+			$this->userManager->expects($this->any())
+				->method('get')
+				->with($uid)
+				->willReturn($this->createUserMock(['uid' => $uid, 'name' => $managerName]));
+		} else {
+			$this->userManager->expects($this->any())
+				->method('get')
+				->with($uid)
+				->willReturn(null);
+		}
+
+		$plugin = $this->getPlugin();
+		$this->assertEquals($expected, self::invokePrivate($plugin, 'createResult', [$type, $uid, $name]));
+	}
+}