use ActiveSupport::TestCase instead of HelperTestCase

ActionView::Helpers::ActiveRecordHelper at test/helper_testcase.rb
does not exist on Rails 3.0.

--HG--
extra : source : a8c76e7910f22e8261f23f0aa73b0a38752d6ef8
use ActionView::TestCase instead of HelperTestCase

ActionView::Helpers::ActiveRecordHelper at test/helper_testcase.rb
does not exist on Rails 3.0.

--HG--
extra : source : 974ee7ecaf8da00e19ca1aa8661938771e48ebb3
Get rid of HelperTestcase.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8278 e93f8b46-1217-0410-a6f0-8f06a7374b81

--HG--
extra : source : 3eb2f1276ca18f771a38f78ad325bfba6d77fef8