acts_as_boolean

_README.md

Acts As Boolean

A quick way to create an attribute on your ActiveRecord models that always responds with a boolean value, similar to the Boolean attributes from a table that have the ? method for syntactic sugar.

class SomeObject < ActiveRecord::Base
  acts_as_boolean :is_active
end

o = SomeObject.new
o.is_active?                  # => false
o.is_active = true
o.is_active?                  # => true
o.is_active = SomeObject.new
o.is_active?                  # => true
o.is_active = nil 
o.is_active?                  # => false

Credits

• @jkreeftmeijer for coming up with the killer MicroGem concept
  (http://jeffkreeftmeijer.com/2011/microgems-five-minute-rubygems/)
• @moutten for the code idea and encouragement to stop creating these methods by hand
• @samshull for making bang-bang such a great inside joke that I had to use it instead of my preferred ternary. :)

acts_as_boolean.gemspec

Gem::Specification.new do |s|
  s.name        = 'acts_as_boolean'
  s.version     = '0.1.0'
  s.platform    = Gem::Platform::RUBY
  s.author      = 'Tim Harvey'
  s.email       = 'tim@theharveys.org'
  s.summary     = 'Acts As Boolean'
  s.description = 'Create question-mark attr_accessor model methods'

  s.files         = ['acts_as_boolean.rb']
  s.test_file     = 'acts_as_boolean_spec.rb'
  s.require_path  = '.'

  s.add_development_dependency('rspec', ["~> 2.0"])
end

acts_as_boolean.rb

module ActsAsBoolean
  def acts_as_boolean(*attributes)
    [*attributes].each do |attribute|

      # Define the = setter method
      attr_writer attribute

      # Define the ? accessor method
      define_method("#{attribute}?") { !!instance_variable_get("@#{attribute}") }

    end
  end
end

ActiveRecord::Base.send :extend, ActsAsBoolean

acts_as_boolean_spec.rb

require File.expand_path('acts_as_boolean')

class ObjectWithActsAsBoolean
  extend ActsAsBoolean
end

describe ActsAsBoolean do
  let(:instance) { ObjectWithActsAsBoolean.new }


  describe '#acts_as_boolean' do
    context 'with an argument of :my_attribute' do
      before(:each) { ObjectWithActsAsBoolean.send :acts_as_boolean, :my_attribute }

      it 'should define a #my_attribute? accessor method' do
        instance.respond_to?(:my_attribute?).should be_true
      end

      it 'should define an #my_attribute= setter method' do
        instance.respond_to?(:my_attribute=).should be_true
      end

      it 'should not define a #my_attribute getter method' do
        instance.respond_to?(:my_attribute).should be_false
      end

      it 'should return false when #my_attribute? is called and my_attribute is nil' do
        instance.my_attribute?.should == false
      end

      it 'should return true when #my_attribute? is called and my_attribute is true' do
        instance.my_attribute = true
        instance.my_attribute?.should == true
      end

      it 'should return false when #my_attribute? is called and my_attribute is false' do
        instance.my_attribute = false
        instance.my_attribute?.should == false
      end
    end

    context 'with two arguments, :my_attribute and :your_attribute' do
      before(:each) { ObjectWithActsAsBoolean.send :acts_as_boolean, :my_attribute, :your_attribute }

      it 'should define a #my_attribute? accessor method' do
        instance.respond_to?(:my_attribute?).should be_true
      end

      it 'should define a #your_attribute? accessor method' do
        instance.respond_to?(:your_attribute?).should be_true
      end

      it 'should return true when #your_attribute? is called and your_attribute is true' do
        instance.your_attribute = true
        instance.your_attribute?.should == true
      end

      it 'should return true when #my_attribute? is called and my_attribute is true' do
        instance.my_attribute = true
        instance.my_attribute?.should == true
      end
    end
  end
end