Some days before when I am writing an application without using ActiveRecord and writing its tests with Rspec, I ran into an error "undefined method `fixture_path=`" when I executes the spec. If you are facing this issue here is how you can fix this error.
I have created this application with -O option for rails command so that it won't use ActiveRecord. I think rspec-rails is not enough intelligent to know this. When I setup the rspec-rails for Rails 3 it generates a spec/spec_helper.rb with ActiveRecord configurations.
To fix it you need to comment out two lines from spec/spec_helper.rb. In the the gist below 2nd and 7th are the lines to comment.
You can also assign false to config.use_transactional_fixtures instead of commenting. So now your spec/spec_helper.rb will look like this.
Hope it worked for you.