Autospec skipping lib/vendor in a Rails project

Question

Hello,

I have a rails project which I am testing with rspec using script/autospec and it has been working great. However, I am now trying to add specs for a Vendor module in spec/lib/vendor/*_spec.rb and autospec ignores the files.

I have tried adding the following to .autotest based on the answer provided here with no success:

Autotest.add_hook :initialize do |at|
  at.add_mapping(%r%^spec/lib/vendor/.*_spec\.rb$%) do
    at.files_matching(%r%^spec/lib/vendor/.*_spec\.rb$%)
  end
end

Executing script/spec spec runs all examples, including those in spec/lib/vendor, with no issues. I am using rails 2.3.8, rspec 1.3.0, rspec-rails 1.3.2 and ZenTest 4.3.2. How can I force autospec to run the examples in spec/lib/vendor?