i can not get current_user while writing test case with Rspec and Capy

have to write test case for my one feature listing page and that feature index method has code like below

def index
  @features = current_user.features
end

Now when i try to write test case for this then it throws error for 'undefined method features for nil class' because it can not get the current user

Now what i have do is below
I have write the login process in the before each statement and then write the test case for the features listing page

Can you please let me know that how i can get the current_user ? FYI, I have used devise gem