Assembly Line
=============

Assembly Line allows you to group together a series of rspec `let` statements which can later be evaluated to set up a specific state for your specs. It's an excellent compliment to factory_girl because you can use your factories to build up each component, then use AssemblyLine to bring them all together.

As a system grows in complexity, more objects are required to set up the necessary state to write tests. Sometimes you'll need to write a test that requires access to the beginning, middle, and end of a very large hierarchy, and AssemblyLine can expose each part of the hierarchy that you care about.  

Installation
------------
    gem install assembly_line

Edit your *spec/spec_helper.rb*  

    require 'assembly_line' # unnecessary if you've used config.gem 'assembly_line'
    require 'spec/support/assemblies' # unnecessary if your spec_helper already requires spec/support/*

    Spec::Runner.configure do |config|
	  config.extend AssemblyLine
	end
	
Define an AssemblyLine

	AssemblyLine.define(:user_with_payment_address) do
	  let(:user) { Factory(:user)}
	  let(:payment_address) { Factory(:payment_address, :user => user) }
	end
	
Example
-------
	
### Place your AssemblyLine definitions in *spec/support/assemblies.rb*

	class Party < Struct.new(:host, :attendees)
	  attr_writer :drinks
	  def drinks
	    @drinks ||= []
	  end
	end

	AssemblyLine.define(:drinks) do
	  let(:drinks) { [:gin, :vodka] }
	end

	AssemblyLine.define(:party) do
	  depends_on :drinks

	  let(:host) { :rochelle }
	  let(:attendees) { [:nick, :ellis, :coach] }
	  let(:party) { @party = Party.new(host, attendees) }
	  let(:party_crasher) { attendees << :crasher; :crasher }
	end
	
### Use your AssemblyLine in a test

	describe "README example" do
	  context "attendees" do
	    Assemble(:party)

	    it "does not count the host as an attendee" do
	      party.attendees.should_not include(host)
	    end
	  end

	  context "party crasher" do
	    Assemble(:party).invoke(:party_crasher)

	    it "exemplifies method invocation after assembly" do
	      party.attendees.should include(:crasher)
	    end
	  end

	  context "drinks" do
	    Assemble(:party)

	    it "does not include the list of standard drinks" do
	      party.drinks.should_not include(drinks)
	    end
	  end
	end
	
### Use your AssemblyLine in an irb session

AssemblyLine works a little differently when using it in irb. Your `let` definitions will not be defined globally (see [e26a903](http://github.com/sandro/commit/e26a903)), instead you'll have to prefix all defined methods with `AssemblyLine`.

	>> Assemble(:drinks)
	=> #<AssemblyLine::Constructor:0x10049e958 @code_block=#<Proc:0x000000010049ea98@(irb):1>, @name=:drinks, @rspec_context=AssemblyLine::GlobalContext, @options={}>
	>>
	>> AssemblyLine.drinks # the `drinks` method is prefixed with AssemblyLine
	=> [:gin, :vodka]
	

Thanks!
-------

- l4rk     (initial spike declaring modules and including them in the rspec context)
- veezus   (code contributions, introduced modular design / dependencies)
- bigtiger (named the project)
- leshill  (support and testing, suggested irb support)
- wgibbs   (suggested irb support)


Note on Patches/Pull Requests
-----------------------------

- Fork the project.
- Make your feature addition or bug fix.
- Add tests for it. This is important so I don't break it in a
  future version unintentionally.
- Commit, do not mess with rakefile, version, or history.
  (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
- Send me a pull request. Bonus points for topic branches.

Copyright
---------

Copyright (c) 2010 Sandro Turriate. See MIT_LICENSE for details.