Testing Helpers in Rails

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, {})

Then in my tests I do something like;

def test\_revision\_link
&lt;a href=\\http://svn.sourceforge.net/viewvc/jikesrvm?view=rev&amp;revision=22\\&gt;22</a>”,

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