Dont make real users in tests

apps/files_sharing/tests/testcase.php

@@ -65,9 +65,11 @@ abstract class TestCase extends \PHPUnit_Framework_TestCase {
 		\OCP\Util::connectHook('OC_Filesystem', 'setup', '\OC\Files\Storage\Shared', 'setup');
 
 		// create users
-		self::loginHelper(self::TEST_FILES_SHARING_API_USER1, true);
-		self::loginHelper(self::TEST_FILES_SHARING_API_USER2, true);
-		self::loginHelper(self::TEST_FILES_SHARING_API_USER3, true);
+		$backend = new \OC_User_Dummy();
+		\OC_User::useBackend($backend);
+		$backend->createUser(self::TEST_FILES_SHARING_API_USER1, self::TEST_FILES_SHARING_API_USER1);
+		$backend->createUser(self::TEST_FILES_SHARING_API_USER2, self::TEST_FILES_SHARING_API_USER2);
+		$backend->createUser(self::TEST_FILES_SHARING_API_USER3, self::TEST_FILES_SHARING_API_USER3);
 
 		// create group
 		\OC_Group::createGroup(self::TEST_FILES_SHARING_API_GROUP1);