Plugin rake task fails in Rails 3

[mratzloff]

I'm getting a bug with Selenium on Rails 3:

$ rails plugin install http://github.com/paytonrules/selenium-on-rails.git
Initialized empty Git repository in [...]/vendor/plugins/selenium-on-rails/.git/
remote: Counting objects: 206, done.
remote: Compressing objects: 100% (171/171), done.
remote: Total 206 (delta 37), reused 169 (delta 26)
Receiving objects: 100% (206/206), 374.13 KiB | 46 KiB/s, done.
Resolving deltas: 100% (37/37), done.
From http://github.com/paytonrules/selenium-on-rails
 * branch            HEAD       -> FETCH_HEAD
$ cd vendor/plugins/selenium-on-rails/
$ rake
(in [...]/vendor/plugins/selenium-on-rails)
/opt/local/bin/ruby1.9 -I"lib:lib" "/opt/local/lib/ruby1.9/1.9.1/rake/rake_test_loader.rb" "test/paths_test.rb" "test/renderer_test.rb" "test/rselenese_test.rb" "test/selenese_test.rb" "test/selenium_controller_test.rb" "test/selenium_on_rails_config_test.rb" "test/selenium_support_test.rb" "test/setup_test.rb" "test/suite_renderer_test.rb" "test/switch_environment_controller_test.rb" 
<internal:lib/rubygems/custom_require>:29:in `require': no such file to load -- test/test_helper (LoadError)
    from <internal:lib/rubygems/custom_require>:29:in `require'
    from test/paths_test.rb:1:in `<top (required)>'
    from /opt/local/lib/ruby1.9/1.9.1/rake/rake_test_loader.rb:5:in `load'
    from /opt/local/lib/ruby1.9/1.9.1/rake/rake_test_loader.rb:5:in `block in <main>'
    from /opt/local/lib/ruby1.9/1.9.1/rake/rake_test_loader.rb:5:in `each'
    from /opt/local/lib/ruby1.9/1.9.1/rake/rake_test_loader.rb:5:in `<main>'
rake aborted!
Command failed with status (1): [/opt/local/bin/ruby1.9 -I"lib:lib" "/opt/l...]
/opt/local/lib/ruby1.9/1.9.1/rake.rb:993:in `block in sh'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1008:in `call'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1008:in `sh'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1092:in `sh'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1027:in `ruby'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1092:in `ruby'
/opt/local/lib/ruby1.9/1.9.1/rake/testtask.rb:115:in `block (2 levels) in define'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1110:in `verbose'
/opt/local/lib/ruby1.9/1.9.1/rake/testtask.rb:100:in `block in define'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:634:in `call'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:634:in `block in execute'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:629:in `each'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:629:in `execute'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:595:in `block in invoke_with_call_chain'
/opt/local/lib/ruby1.9/1.9.1/monitor.rb:201:in `mon_synchronize'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:588:in `invoke_with_call_chain'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:605:in `block in invoke_prerequisites'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:602:in `each'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:602:in `invoke_prerequisites'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:594:in `block in invoke_with_call_chain'
/opt/local/lib/ruby1.9/1.9.1/monitor.rb:201:in `mon_synchronize'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:588:in `invoke_with_call_chain'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:581:in `invoke'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:2041:in `invoke_task'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:2019:in `block (2 levels) in top_level'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:2019:in `each'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:2019:in `block in top_level'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:2058:in `standard_exception_handling'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:2013:in `top_level'
/opt/local/lib/ruby1.9/1.9.1/rake.rb:1992:in `run'
/opt/local/bin/rake:31:in `<main>'