Using RSpec to test HAML helpers
Posted by Jim Morris Sat, 14 Jul 2007 23:40:00 GMT
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...
module ApplicationHelper
...
def display_flash
for name in [:notice, :warning, :error]
if flash[name]
haml_tag :div, flash[name], {:class => name.to_s}
end
end
nil
end
...
endThis 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...
# File: spec/helpers/application_helper_spec.rb
require File.dirname(__FILE__) + '/../spec_helper'
describe ApplicationHelper do
before :each do
helper.extend Haml
helper.extend Haml::Helpers
helper.send :init_haml_helpers
end
it "should display flash" do
for name in [:notice, :warning, :error]
flash[name]= "flash #{name.to_s} message"
helper.capture_haml{
helper.display_flash
}.should =~ /<div class='#{name.to_s}'>\s*#{flash[name]}\s*<\/div>/
flash[name]= nil
end
end
endExcellent, 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...
# display a tag cloud for the given model
def tag_cloud(model, title= nil)
m= model.to_s.camelcase.constantize
plural= model.to_s.capitalize.pluralize
title ||= plural
tags= m.tag_counts(:order => 'tags.name')
return false if tags.empty?
urlmeth= "tagged_#{model.to_s.pluralize}_path".to_sym
haml_tag :div, {:class => "tagcloud"} do
haml_tag :h3, title
tags.each do |t|
next if t.name == 'FAQ'
haml_tag :span, {:style => "font-size:#{calc_size(t.count)}%"} do
puts link_to(h(t.name), self.send(urlmeth, :tag => t.name))
end
end
end
return true
end 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.
