RSpec for View Helpers

• To test a view helper, you need to test the plugin in the context of a rails app
• To verify that you can put the following code into your spec_helper.rb (or just use rspec-plugin-generator by Pat Maddox which will generate this code for you)

  begin
    require File.dirname(__FILE__) + '/../../../../spec/spec_helper'
  rescue LoadError
    puts "You need to install rspec in your base app"
    exit
  end

• By convention, helper examples live in spec/helpers/ then their dependencies will get magically included.   David Chelimsky notes
  

  All directories under spec/ are potentially magic – rspec will always
  look at spec/:directory/:filename and see if it has an example group
  type registered for whatever directory is. So if there *is* a foo
  example group type, it will be used for any spec file in spec/foos

• If you put helpers elsewhere, then you need to declare their type (or manually include dependencies)

  describe AppletHelper, :type => :helper do

• To send params in your test, you can just define them before calling your view helper.  For example:

  describe DogHelper do
    it "should bark" do
      params[:debug] = "foo"
      html = helper.bark
      html.should have_tag("script")
    end
  end

What do you do when some behavior depends on RAILS_ENV?

• It’s not a good practice to switch around RAILS_ENV in the test framework
• Better idea is use a method to check it and then stub that out
• Here’s an outline:  gist from Zach
• Here’s what I did: EnvChecker, code and example

Stub tip

If you stub something and it appears not to be working, check when your module, class or method is loaded or created.  Dynamic languages can be challenging.  (thanks David)

References

For more information, see

• The RSpec Book
• rspec doc
• rspec-rails doc
• Zach’s code review recap

These lessons learned while developing RSpec examples for a bug fix in openlaszlo_plugin with help from Zach Moazeni, RailsBridge mentor, and David Chelmsky, on the RSpec forum.