macro example and variations

01_original_customer_spec.rb

describe Customer, "last billing address" do
  before do
    @customer = Customer.generate!  
    @customer = Address.new
  end
  it "should be settable and gettable" do
    @customer.last_billing_address = @account_address
    @customer.last_billing_address.should == @account_address
  end  
  ...  
end

describe Customer, "last delivery address" do
  before do
    @customer = Customer.generate!  
    @account_address = Address.new
  end
  it "should be settable and gettable" do
    @customer.last_delivery_address = @account_address
    @customer.last_delivery_address.should == @account_address
  end
end

02_orginal_shared_example_spec.rb

share_examples_for "named address" do

  it "should be settable and gettable" do
    named_address = @account_address
    @named_address.should == @account_address
  end  
end  

describe Customer, "last billing address" do 
  it_should_behave_like "named address"

  before do
    named_address = @customer.last_billing_address=
    @named_address = @customer.last_billing_address

03_simple_macro_spec.rb

class Customer
  attr_accessor :last_delivery_address, :last_billing_address
end

module AccessorMacro

  def it_should_have_an_accessor_for(*attributes)
    attributes.each do |attribute|
      describe attribute do
        it "should be settable and gettable" do
          reader = attribute.gsub(' ','_')
          writer = "#{reader}="
          @customer.send(writer,'some value')
          @customer.send(reader).should == 'some value'
        end
      end
    end
  end

end

describe Customer do
  before do
    @customer = Customer.new
  end
  extend AccessorMacro

  it_should_have_an_accessor_for('last billing address', 'last delivery address')

end

04_how_i_would_word_it_if_I_thought_it_was_a_good_idea_spec.rb

class Customer
  attr_accessor :last_delivery_address, :last_billing_address
end

module AccessorMacro

  def it_should_have_an_accessor_for(*attributes)
    attributes.each do |attribute|
      it "has an accesor for #{attribute}" do
        reader = attribute.to_s.gsub(' ','_')
        writer = "#{reader}="
        @customer.send(writer,'some value')
        @customer.send(reader).should == 'some value'
      end
    end
  end

  alias :it_has_accessors_for :it_should_have_an_accessor_for

end

describe Customer do
  before do
    @customer = Customer.new
  end
  extend AccessorMacro

  it_has_accessors_for :last_billing_address, :last_delivery_address

end

05_instance_var_magic_spec.rb

class Customer
  attr_accessor :last_delivery_address, :last_billing_address
end

module AccessorMacro

  def it_should_have_an_accessor_for(*attributes)
    attributes.each do |attribute|
      it "has an accesor for #{attribute}" do
        reader = attribute.to_s.gsub(' ','_')
        writer = "#{reader}="
        described_object = instance_variable_get("@#{self.class.described_type.to_s.downcase}") || self.class.described_type.new
        described_object.send(writer,'some value')
        described_object.send(reader).should == 'some value'
      end
    end
  end

  alias :it_has_accessors_for :it_should_have_an_accessor_for

end

describe Customer do
  before do
    @customer = Customer.new
  end
  extend AccessorMacro

  it_has_accessors_for :last_billing_address, :last_delivery_address

end

06_use_subject_instead_of_magic_spec.rb

class Customer
  attr_accessor :last_delivery_address, :last_billing_address
end

module AccessorMacro

  def it_should_have_an_accessor_for(*attributes)
    attributes.each do |attribute|
      it "has an accesor for #{attribute}" do
        reader = attribute.to_s.gsub(' ','_')
        writer = "#{reader}="
        subject.send(writer,'some value')
        subject.send(reader).should == 'some value'
      end
    end
  end

  alias :it_has_accessors_for :it_should_have_an_accessor_for

end

describe Customer do
  # This isn't really needed, but it shows how you would define a subject with your current setup.
  #before do
    #@customer = Customer.new
  #end
  #subject { @customer }
  extend AccessorMacro

  it_has_accessors_for :last_billing_address, :last_delivery_address

end

07_maybe_an_eval_is_better_spec.rb

class Customer
  attr_accessor :last_delivery_address, :last_billing_address
end

module AccessorMacro

  def it_should_have_an_accessor_for(*attributes)
    attributes.each do |attribute|
      class_eval(<<-END_OF_MACRO, __FILE__, __LINE__ + 1)
        it "has an accesor for #{attribute}" do
          subject.#{attribute}= 'some value'
          subject.#{attribute}.should == 'some value'
        end
      END_OF_MACRO
    end
  end

  alias :it_has_accessors_for :it_should_have_an_accessor_for

end

describe Customer do
  extend AccessorMacro
  it_has_accessors_for :last_billing_address, :last_delivery_address

end

08_eval_with_spoofed_backtrace_spec.rb

class Customer
  attr_accessor :last_delivery_address, :last_billing_address
end

module AccessorMacro

  def it_should_have_an_accessor_for(*attributes)
    source_filename, source_line = caller[0].split
    attributes.each do |attribute|
      class_eval(<<-END_OF_MACRO, source_filename, source_line.to_i)
        it "has an accesor for #{attribute}" do
          subject.#{attribute}= 'some value'
          subject.#{attribute}.should == 'some value'
        end
      END_OF_MACRO
    end
  end

  alias :it_has_accessors_for :it_should_have_an_accessor_for

end

describe Customer do
  extend AccessorMacro
  it_has_accessors_for :last_billing_address, :last_delivery_address

end