added rspec test for sprite command

spec/compass/commands/sprite_spec.rb

@@ -0,0 +1,49 @@
+require 'spec_helper'
+require 'compass/commands'
+require 'compass/exec'
+require 'compass/commands/sprite'
+describe Compass::Commands::Sprite do
+  def config_data
+    return <<-CONFIG
+      images_path = #{@images_tmp_path.inspect}
+    CONFIG
+  end
+  
+  def create_temp_cli_dir
+    directory = File.join(File.expand_path('../', __FILE__), 'test')
+    ::FileUtils.mkdir_p directory
+     @test_dir = directory
+  end
+  
+  def run_compass_with_options(options)
+    output = 'foo'
+    ::Dir.chdir @test_dir do
+      output = Compass::Exec::SubCommandUI.new(options).run!
+    end
+    output
+  end
+  
+  def options_to_cli(options)
+    options.map.flatten!
+  end
+  
+  let(:test_dir) { @test_dir }  
+  before :each do
+    create_temp_cli_dir
+    create_sprite_temp
+    File.open(File.join(@test_dir, 'config.rb'), 'w') do |f|
+      f << config_data
+    end
+  end
+  after :each do
+    clean_up_sprites
+    FileUtils.rm_r @test_dir if File.exists?(@test_dir)
+  end
+  
+  it "should create sprite file" do
+    puts run_compass_with_options(['sprite', "-f", "stylesheet.scss", "'#{@images_tmp_path}/*.png'"]).inspect
+    File.exists?(File.join(test_dir, 'stylesheet.scss')).should be_true
+  end
+  
+  
+end