Added rake test task

Rakefile

@@ -42,16 +42,21 @@ rescue LoadError
   puts "Jeweler (or a dependency) not available. Install it with: sudo gem install jeweler"
 end
 
+require 'rake/testtask'
+Rake::TestTask.new do |t|
+  t.libs = ["lib", "test"]
+end
+
+extra_files = %w[LICENSE.txt THANKS.txt CHANGES.txt ]
 RDoc::Task.new do |rdoc|
   rdoc.rdoc_dir = "rdoc"
   rdoc.title = "#{name} #{version}"
   rdoc.generator = 'hanna' # gem install hanna-nouveau
   rdoc.main = 'README.rdoc'
   rdoc.rdoc_files.include("README*")
-  rdoc.rdoc_files.include("LICENSE.txt")
-  rdoc.rdoc_files.include("THANKS.txt")
-  rdoc.rdoc_files.include("CHANGES.txt")
   rdoc.rdoc_files.include("bin/*.rb")
   rdoc.rdoc_files.include("lib/**/*.rb")
+  extra_files.each { |file|
+    rdoc.rdoc_files.include(file) if File.exists?(file)
+  }
 end
-