fix tests running

Author: denofevil

test/rd_test_base.rb

@@ -22,7 +22,7 @@ def debug_command(script, port)
     cmd = "#{interpreter}"
     cmd << " --debug" if jruby?
     cmd << " -J-Xdebug -J-Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=y" if jruby? and debug_jruby?
-    cmd << " -I '#{File.dirname(script)}' #{@rdebug_ide}" +
+    cmd << " -I 'lib:#{File.dirname(script)}' #{@rdebug_ide}" +
       (@verbose_server ? " -d" : "") +
       " -p #{port} -- '#{script}'"
   end