adding unit test to truncate the table

apps/user_ldap/lib/helper.php

@@ -172,7 +172,7 @@ class Helper {
 	}
 
 	/**
-	 * extractsthe domain from a given URL
+	 * extracts the domain from a given URL
 	 * @param string $url the URL
 	 * @return string|false domain as string on success, false otherwise
 	 */

apps/user_ldap/tests/helper.php

+<?php
+/**
+* ownCloud
+*
+* @author Thomas Müller
+* @copyright 2014 Thomas Müller deepdiver@owncloud.com
+*
+*/
+
+namespace OCA\user_ldap\tests;
+
+use OCA\user_ldap\lib\Helper;
+
+class Test_Helper extends \PHPUnit_Framework_TestCase {
+
+	public function testTableTruncate() {
+
+		$statement = \OCP\DB::prepare('INSERT INTO `*PREFIX*ldap_user_mapping` (`ldap_dn`, `owncloud_name`, `directory_uuid`) VALUES (?, ?, ?)');
+		$statement->execute(array('db01', 'oc1', '000-0000-0000'));
+		$statement->execute(array('db02', 'oc2', '000-0000-0001'));
+
+		$statement = \OCP\DB::prepare('SELECT count(*) FROM `*PREFIX*ldap_user_mapping`');
+		$result = $statement->execute();
+		$this->assertEquals(2, $result->fetchOne());
+
+		Helper::clearMapping('user');
+
+		$result = $statement->execute();
+		$this->assertEquals(0, $result->fetchOne());
+	}
+}