Exercise solution

configure.rb

class Configuration
  attr_accessor :tail_logs
  attr_accessor :max_connections
  attr_accessor :admin_password
  
  def initialize
    @app_server = AppServer.new
  end
  
  def app_server
    yield @app_server if block_given?
    @app_server
  end
  class AppServer
    attr_accessor :port
    attr_accessor :admin_password
  end
end



def configure
  c = Configuration.new
  yield c if block_given?
  c
end

configuration = configure do |config|  
  config.tail_logs = true  
  config.max_connections = 55  
  config.admin_password = 'secret'  
  config.app_server do |app_server_config|  
    app_server_config.port = 8808  
    app_server_config.admin_password = config.admin_password  
  end  
end  
  
puts configuration.class # => Configuration  
puts configuration.tail_logs # => true  
puts configuration.app_server.admin_password # => 'secret'

configure_spec.rb

require File.expand_path(File.dirname(__FILE__) + '/../lib/configure')

describe "configurate" do
    
  it "it accepts a block with an object" do
    configure do |config|
      config.tail_logs = true
    end.tail_logs.should be_true
  end
  
  it "is possible to configure app server" do
    configure do |config|
      config.app_server do |app_server|
        app_server.admin_password = "secret"
      end
    end.app_server.admin_password.should == "secret"
  end
  
  it "is possible to reconfigure app server" do
    conf = configure do |c|
      c.app_server do |a|
        a.port = 1336
      end
    end
    conf.app_server.port.should == 1336
    conf.app_server.port = 1337
    
    conf.app_server.port.should == 1337  
      
    
  end
end


describe Configuration::AppServer do
  it { should respond_to(:port)}
  it { should respond_to(:admin_password)}
end

describe Configuration do
  it {should respond_to(:tail_logs)}
  it {should respond_to(:max_connections)}
  it {should respond_to(:admin_password)}
  it "has a method app_server" do
    Configuration.new.should respond_to(:app_server)
  end
  
  describe "#app_server" do
    it "returns instance of AppServer" do
      Configuration.new.app_server.should be_a(Configuration::AppServer)
    end
    it "passes arguments given in a block" do
      mock_server = double("appserver")
      mock_server.should_receive(:foo=).with("bar")
      Configuration::AppServer.stub!(:new).and_return(mock_server)
      Configuration.new.app_server do |app_server|
        app_server.foo = "bar"
      end
    end
  end
end