Rcov and Shoulda How to evaluate Code Coverage?

Hi I am using rcov to measure code coverage by testings made with Shoulda, mainly functional tests I assumed that calling an action in the test procedure would cover all the code in that action, that the params values activate For example in my functional test I use get :index which should activate most of the code in the index action, but rcov tells me that no code in the index action is executed by ruby and that the code coverage is only 17.5 %

Have I installed the wrong rcover. I use rails 2.3.8 and Shoulda and rcov 0.9.11? In my application rake file I define the following rake task (according to what I found using googel) Is there a better rake task to use ?

Would very much appreciate any advices !!!