RealityForge.org: Testing Helpers in Rails

Testing Helpers in Rails

Peter Donald — Thu, 14 Jun 2007 00:01:00 +1000

It can be useful at times to unit test helpers to make sure they generate correct html. It is not obvious how to do this at first. So far I have been testing my helper by defining a class “MyClass” at the top of my unit test and including all the appropriate modules. I also need to define a url_for method if I ever want to test helpers that generate links.

The code follows (Replace MyHelper with your appropriate helper class);

class MyClass
  include ERB::Util
  include ActionView::Helpers::TagHelper
  include ActionView::Helpers::UrlHelper
  include MyHelper

  def url_for(options)
    ActionController::Routing::Routes.reload if ActionController::Routing::Routes.empty?
    generated_path, extra_keys = ActionController::Routing::Routes.generate_extras(options, {})
    generated_path
  end
end

Then in my tests I do something like;

def test_revision_link
  assert_equal(
    "<a href=\"http://svn.sourceforge.net/viewvc/jikesrvm?view=rev&amp;revision=22\">22</a>", 
    MyClass.new.revision_link(22))
end

Seems easy enough to do in retrospect but things usually do.

"Testing Helpers in Rails" by Peter Donald

Wed, 04 Jul 2007 11:17:00 +1000

Looks like I should have explicitly set the version in the raaa plugin as it recently changed and that is what broke eyelook. As for the rest – well true it may look ugly but I moved my photos to smugmug (see http://www.realityforge.org/articles/2006/07/03/moving-from-eyelook-to-smugmug)

"Testing Helpers in Rails" by Michael

Mon, 02 Jul 2007 05:12:06 +1000

Tons of errors in eyelook: look for access_denied!, find_active_user and check sqlite compatibility (either drop foreign key constraints (nearly useless in rails either) or add support to active_record_extensions. Layout looks awfull in Safari 3.0 And is a permalink self-explanatory?

"Testing Helpers in Rails" by Luke Melia

Thu, 14 Jun 2007 23:50:58 +1000

The ZenTest gem from Ryan Davis and Eric Hodel adds support for testing Rails helpers. That aspect is not well documented, but it’s in there.