throw 101 when an empty group string is provided

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

apps/provisioning_api/lib/Controller/UsersController.php

@@ -604,7 +604,7 @@ class UsersController extends OCSController {
 	public function removeFromGroup($userId, $groupid) {
 		$loggedInUser = $this->userSession->getUser();
 
-		if($groupid === null) {
+		if($groupid === null || trim($groupid) === '') {
 			throw new OCSException('', 101);
 		}
 

apps/provisioning_api/tests/Controller/UsersControllerTest.php

@@ -2117,6 +2117,20 @@ class UsersControllerTest extends TestCase {
 		$this->api->removeFromGroup('TargetUser', null);
 	}
 
+	/**
+	 * @expectedException \OCP\AppFramework\OCS\OCSException
+	 * @expectedExceptionCode 101
+	 */
+	public function testRemoveFromGroupWithEmptyTargetGroup() {
+		$loggedInUser = $this->getMockBuilder('\OCP\IUser')->disableOriginalConstructor()->getMock();
+		$this->userSession
+			->expects($this->once())
+			->method('getUser')
+			->will($this->returnValue($loggedInUser));
+
+		$this->api->removeFromGroup('TargetUser', '');
+	}
+
 	/**
 	 * @expectedException \OCP\AppFramework\OCS\OCSException
 	 * @expectedExceptionCode 102