rspec users - Nov 2007 - Specs for Helpers that call render

The helper spec I am writing tests a helper method that calls render.

##
module HelperHelper
   def render_partial
     render :partial => ''partial''
   end
end
##

The helper spec.

##
describe HelperHelper do
   it "should render partial" do
     render_partial.should_not == nil
   end
end
##

The output generated

##
$ spec spec/helpers/home_helper_spec.rb
.F

1)
NoMethodError in ''HelperHelper should render partial''
You have a nil object when you didn''t expect it!
The error occurred while evaluating nil.render
app/helpers/helper_helper.rb:4:in `render_partial''
./spec/helpers/helper_helper_spec.rb:3:

Finished in 0.00000 seconds

1 example, 1 failure
##

I tried adding a before(:each) to setup response, controller, and  
template objects that render would be called on but the error was  
always the same.  I am still uncertain I did this correctly although  
I did spend some time looking at the render definition in the rails  
source.

Is there a standard way of setting up specs for helpers that call  
render?

- Peter

(I apologize if this has already been answered.  We spent a good deal  
of time searching around the web for a solution but came up empty so  
far.)

On Nov 2, 2007 8:32 PM, Peter <peter at netsprout.com>
wrote:
> The helper spec I am writing tests a helper method that calls render.
>
> ##
> module HelperHelper
>    def render_partial
>      render :partial => ''partial''
>    end
> end
> ##
>
> The helper spec.
>
> ##
> describe HelperHelper do
>    it "should render partial" do
>      render_partial.should_not == nil
>    end
> end
> ##
>
> The output generated
>
> ##
> $ spec spec/helpers/home_helper_spec.rb
> .F
>
> 1)
> NoMethodError in ''HelperHelper should render partial''
> You have a nil object when you didn''t expect it!
> The error occurred while evaluating nil.render
> app/helpers/helper_helper.rb:4:in `render_partial''
> ./spec/helpers/helper_helper_spec.rb:3:
>
> Finished in 0.00000 seconds
>
> 1 example, 1 failure
> ##
>
> I tried adding a before(:each) to setup response, controller, and
> template objects that render would be called on but the error was
> always the same.  I am still uncertain I did this correctly although
> I did spend some time looking at the render definition in the rails
> source.
>
> Is there a standard way of setting up specs for helpers that call
> render?
Helper specs create an object to run in and include a standard set of
helpers and the helper you are spec''ing. There is no access to
services that come from the controllers or views the helper gets mixed
into when the app is running.

I would just set a message expectation on self, like this:

describe HelperHelper do
  it "should render partial" do
    self.should_receive(:render).with(:partial =>
''partial'')
    render_partial
  end
end

HTH,
David