Add another test.

tests/lib/tags.php

@@ -94,7 +94,7 @@ class Test_Tags extends PHPUnit_Framework_TestCase {
 
 		$this->assertEquals(0, count($tagMgr->getTags()));
 		$this->assertTrue($tagMgr->isEmpty());
-		$tagMgr->add('Tag');
+		$this->assertNotEquals(false, $tagMgr->add('Tag'));
 		$this->assertFalse($tagMgr->isEmpty());
 	}