Using RSpec to test HAML helpers
Posted by Jim Morris on Sat Jul 14 16:44:33 -0700 2007
UPDATED for HAML 2.0 and RSpec 1.1.5 - Changed open to haml_tag, prefix helper. to all rspec calls...
The most recent release of HAML introduced a neat feature that allows you to use HAML-like syntax in your helpers to generate HTML HAML#haml_tag.
A question on the HAML news group asked how to test a helper that uses HAML#haml_tag (used to be open/puts) and thanks to Nathan on that list I finally got RSpec to do it. As shown below.
However a really good point was made that really in RSpec the way to test anything is to use mocks to mock any call to an outside method thus focusing the test on the specific module under test. Generally I agree with that philosophy. But this is way cool so I thought I'd do it anyway, and also as it is a new feature in HAML one may not want to simply trust HAML to generate the correct HTML.
So in my application_helper.rb I have a simple helper...
This is called in my views as...
- display_flash
Notice the - instead of =, this is because the open (and puts) write output directly to the HAML buffer, and so this routine should return nothing. (This is also a very simply case and does not show off the utility of the open/puts methods, I'll show one of those later on).
The RSpec helper test that tests this is as follows...
Excellent, a simple test for the HTML generated by my haml helper. NOTE the setup required in the before :each, this sets up the haml helpers in the helpers context
Why would I want to use HAML#open you ask?
Well it makes the helpers look so much tidier IMHO, take this example from my previous post on tag clouds, the re-factored helper now looks like this...
So much cleaner, plus I can return a boolean to indicate if there was
anything output or not, which tells me if I need to output an <hr/> or
not.
I guess the file you will put that in will be spec/helpers/application_spec.rb
Because you, and http://rspec.rubyforge.org/documentation/rails/writing/helpers.html don't specify the file naming. I took a guess, and it seems to be okey ...
Thanks for the helper, and the spec for the helper! :)
Do you know of any repository of small+usefull helpers that one would usually put in application helpers? That kind of helpers that you take with you to each new application you write ....
Like for example (that I have in my apps):
def whitespace(times = 1)
" " * times
end
Yes that is where I put it.
I'm not aware of a place for those helpers, but if you find one let me know :)
<pre>
it "should display flash" do
for name in [ :notice, :warning, :error ]
flash[name]= "flash #{name.to_s} message"
capture_haml {
display_flash
}.should have_tag "div.#{name.to_s}", 1, :text => flash[name]
end
end
</pre>
Ohh... I actually just used :
<pre>
before(:each) do
@haml_is_haml = true
@haml_stack = [Haml::Buffer.new(:attr_wrapper => "'")]
end
</pre>
<br/>
because I have more haml helpers to test than just one.
Thanks I wasn't sure that ` have_tag` would work, but its good to know thats an option.
Is there a way to add those
include ActionView::Helpers
include Haml::Helpers
into spec_helper.rb ?
and perhaps even the `@haml_is_haml` and `@haml_stack` ....
It's kind of annoying adding those to each description I have of helpers. Not DRY at all. Especially for a non-rails project I am working on.
One can also use automatic inclusion for haml helpers for all helper tests<br/>
by editing `spec/spec_helper.rb`, like so:
Spec::Runner.configure do |config|
config.include Haml::Helpers
config.include ActionView::Helpers
config.before(:each, :behaviour_type => :helper) do
@haml_is_haml = true
@haml_stack = [Haml::Buffer.new(:attr_wrapper => "'")]
end
end
Or if using Haml trunk, then you can also do it like so:
Spec::Runner.configure do |config|
config.before(:each, :behaviour_type => :helper) do
init_haml_helpers
end
end
Though I didn't test this enough, and it could be a bit wrong ... especially regarding the trunk method.
That's very nice. I learn something new every day.
Thank you!