In the Spotlight - Matthew Bass

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.

Raleigh’s first RubyCamp is coming to Red Hat on October 18th. This is a similar format to BarCamp in that the presentations are pitched the morning of the conference, and attendees self organize the remainder of the day. Relevance will be running their popular Refactotum workshop in the morning. The conference is free, but attendance is capped at 200 so visit the wiki to grab your spot.

vizres renders the body of an HTTP response from inside a Rails functional test. It used to be a plugin, but now it’s a gem. Why? Because Rails gems are the new hotness. Now go get it.

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 on your system:

gem sources -a http://gems.github.com
sudo gem install pelargir-finder_filter

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.

BarCampRDU 2008 came and went. It was quite enjoyable. There wasn’t as much grub as last year, but I thought the topics were more interesting.

I gave a talk on pair programming during the afternoon. It really became more of a group discussion, which was exactly what I was hoping for. Some attendees have requested the slides so I’ve attached them to this post as a PDF.

The slides have been edited somewhat. I gave this same presentation at Agile ITX last month and it was an hour and a half long. I had to cut out a few things for BarCamp. But the central ideas are still there.