how can I test the plugin install command?

Hi,

I've submited a patch that solves credential issues with web
repositories (http://dev.rubyonrails.org/ticket/11351) but I have a
problem with the test.

Basicly, I don't know how and where should I add the test. I've seen
that a class called "plugin_test.rb" exists but it has the same
behaviour as script/plugin and it needs two command line arguments.
Moreover I can't load the file 'commands/plugin.rb' because
Commands::Plugin needs a correct RailsEnvironment that I can't replace
with a mock because it's in the same file as Commands::Plugin.

Anyone can explain me how can I add a test for install plugins command?