failure in ActionMailer tests due to load issue

It looks like active_support from gems instead of the checked out copy is getting loaded in the action mailer tests, resulting in the error seen below:

(in /Users/rsanheim/src/relevance/rails_src/actionmailer)
/opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake/rake_test_loader.rb" "test/delivery_method_test.rb" "test/mail_helper_test.rb" "test/mail_layout_test.rb" "test/mail_render_test.rb" "test/mail_service_test.rb" "test/quoting_test.rb" "test/test_helper_test.rb" "test/tmail_test.rb" "test/url_test.rb"
/opt/local/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/layout.rb:8:in `alias_method': undefined method `render' for class `ActionMailer::Base' (NameError)
	from /opt/local/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/layout.rb:8:in `included'
	from /opt/local/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/layout.rb:5:in `class_eval'
	from /opt/local/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/layout.rb:5:in `included'
	from ./test/../lib/action_mailer/base.rb:251:in `include'
	from ./test/../lib/action_mailer/base.rb:251
	from /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
	from /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require'
	from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:509:in `require'
	 ... 9 levels...
	from /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake/rake_test_loader.rb:5:in `load'
	from /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake/rake_test_loader.rb:5
	from /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake/rake_test_loader.rb:5:in `each'
	from /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake/rake_test_loader.rb:5
rake aborted!
Command failed with status (1): [/opt/local/bin/ruby -Ilib:test "/opt/local...]

See also this related bug:

http://rails.lighthouseapp.com/p...