Sprockets to use config.assets.prefix, with tests

[docunext]

A simple change to actionpack/lib/sprockets/helpers/rails_helpers.rb, based off this previous commit:

2684f17

which I found when encountering this problem:

http://www.ruby.code-experiments.com/blog/2011/09/a-problem-with-the-rails-31-asset-pipeline.html

I would appreciate feedback on the tests, specifically the "alternate asset prefix" test on line 345 of the updated sprockets_helper_test.rb.

Albert

[spastorino]

I think just one test like ...

test "custom_asset_path" do
  @config.assets.prefix = '/s'
  assert_match %r{/s/logo-[0-9a-f]+.png},
  asset_path("logo.png")
end

is enough.

[docunext]

I am not familiar with the difference between stubs(:asset_prefix).returns("/themes/test") and @config.assets.prefix = '/s'. They appear to be the same, however it is not clear why the former apparently worked prior to this commit.

[spastorino]

stubs method generate a stub for asset_prefix method, so when you invoke this method will always return "/themes/test". Using @config.assets.prefix = '/s' you're just configuring the prefix and using it you're testing properly without stubs, so go with @config.assets.prefix = '/s'

[docunext]

Great! I will simplify the test later today and recommit.

[spastorino]

Remember to squash all the commits into one and push -f to your master branch

[docunext]

OK, that is done. Let me know if anything further is required, and thank you for the collaboration.

[docunext]

Do I need to close the pull request to indicate that its ready to go, or does that cancel the request?