Generate autotest configuration.

Closes #10.

features/command_line/configure.feature

@@ -0,0 +1,19 @@
+Feature: configure
+
+  Use --configure to generate configuration files.
+
+  Currently, the only supported argument is "autotest", which creates
+  a autotest/discover.rb file in your project root directory.
+
+  Background:
+    Given a directory named "rspec_project"
+    And I cd to "rspec_project"
+
+  Scenario: generate autotest directory and discover file
+    When I run "rspec --configure autotest"
+    Then the following directories should exist:
+      | autotest |
+    And the following files should exist:
+      | autotest/discover.rb |
+    And the file "autotest/discover.rb" should contain "Autotest.add_discovery"
+    And the stdout should contain "autotest/discover.rb has been added"

lib/rspec/core.rb

@@ -13,6 +13,7 @@
 require 'rspec/core/around_proxy'
 require 'rspec/core/world'
 require 'rspec/core/configuration'
+require 'rspec/core/command_line_configuration'
 require 'rspec/core/option_parser'
 require 'rspec/core/configuration_options'
 require 'rspec/core/command_line'

lib/rspec/core/command_line_configuration.rb

@@ -0,0 +1,53 @@
+module RSpec
+  module Core
+    class CommandLineConfiguration
+      attr_reader :command
+
+      def initialize(cmd)
+        @command = cmd
+      end
+
+      def run
+        case @command
+        when 'autotest' then Autotest.generate
+        else raise ArgumentError, "#{@command} is not a valid option"
+        end
+      end
+
+      class Autotest
+        class << self
+          def generate
+            create_autotest_directory
+            create_discover_file
+            puts "autotest/discover.rb has been added"
+          end
+
+          def create_autotest_directory
+            Dir.mkdir('autotest') unless File.exist?('autotest')
+          end
+
+          def create_discover_file
+            optionally_remove_discover_file if discover_file_exists?
+            File.open(discover_file_path, 'w') do |file|
+              file << 'Autotest.add_discovery { "rspec2" }'
+            end
+          end
+
+          def optionally_remove_discover_file
+            print "Discover file already exists, overwrite [y/N]? "
+            exit if gets !~ /y/i
+            FileUtils.rm_rf(discover_file_path)
+          end
+
+          def discover_file_exists?
+            File.exist?(discover_file_path)
+          end
+
+          def discover_file_path
+            File.join('autotest', 'discover.rb')
+          end
+        end
+      end
+    end
+  end
+end

lib/rspec/core/option_parser.rb

@@ -86,10 +86,14 @@ def parser(options)
           options[:drb] = true
         end
 
+        parser.on('--configure COMMAND', 'Generate configuration files') do |cmd|
+          CommandLineConfiguration.new(cmd).run
+          exit
+        end
+
         parser.on('--drb-port [PORT]', 'Port to connect to on the DRb server') do |o|
           options[:drb_port] = o.to_i
         end
-
       end
     end
   end

spec/rspec/core/command_line_configuration_spec.rb

@@ -0,0 +1,26 @@
+require 'spec_helper'
+
+module RSpec::Core
+  describe CommandLineConfiguration do
+    describe '#run' do
+      context 'given autotest command' do
+        let(:config) { described_class.new('autotest') }
+
+        it 'calls Autotest.generate' do
+          described_class::Autotest.should_receive(:generate)
+          config.run
+        end
+      end
+
+      context 'given unsupported command' do
+        let(:config) { described_class.new('unsupported') }
+
+        it 'raises ArgumentError' do
+          lambda { config.run }.should(
+            raise_error(ArgumentError, 'unsupported is not a valid option')
+          )
+        end
+      end
+    end
+  end
+end