Month: August 2008

I just released a new gem on GitHub that provides some common validation expectations to rspec. Instead of writing specs to verify that your models are handling validation correctly, these expectations simply check that the validation is getting declared correctly in your model. For example:

describe User do
  it_should_validate_presence_of :first_name, :last_name, :email
  it_should_validate_numericality_of :zip
  it_should_validate_uniqueness_of :email
end

Since the expectations never hit the database, they are also faster than testing the traditional way. It’s dead simple to install on Rails 2.1 or later:

script/plugin install git://github.com/pelargir/rspec_validation_expectations.git

The expectations become available to your specs immediately.

I’m at the Ruby Hoedown in Huntsville this weekend. Being around so many brilliant geeks encouraged me to release a gem I’ve had sitting in the hopper for several weeks.

finder_filter encapsulates a pattern I find myself using quite frequently in Rails. Namely, looking up an instance variable before an action. For example:

class UsersController < ActionController::Base
  before_filter :find_user, :only => [:show, :edit]
  
  def show
    # do something with @user
  end
  
  def edit
    # do something with @user
  end
  
  def find_user
    @user = User.find(params[:id)
  end
end

Sticking the finder in a before filter keeps the code DRY, but it still takes several lines to do this. finder_filter reduces this to a single line of code:

class UsersController < ActionController::Base
  finder_filter :only => [:show, :edit]
  
  def show; end
  def edit; end
end

There are other options to customize the column and param used in the lookup. Check out the README for full details.

To install the gem as a plugin in your Rails project:

sudo gem install pelargir-finder_filter --source=http://gems.github.com

Then open environment.rb in your Rails app and add the gem as a dependency in your initializer block:

Rails::Initializer.run do |config| 
  config.gem "pelargir-finder_filter"
  ...
end

If you have any comments or suggestions, I’d love to hear from you. Contact me through the finder_filter project on GitHub.