Adds some helpers tests.

git-svn-id: http://svn.redmine.org/redmine/trunk@13735 e93f8b46-1217-0410-a6f0-8f06a7374b81
Adds a test for search with limited results.

git-svn-id: http://svn.redmine.org/redmine/trunk@13736 e93f8b46-1217-0410-a6f0-8f06a7374b81
Revert r13736, test fails with mysql.

git-svn-id: http://svn.redmine.org/redmine/trunk@13737 e93f8b46-1217-0410-a6f0-8f06a7374b81