In Rails 3, I'm getting a NoMethodError for the recycle! method during testing

Question

Hello,

I've got a functional test that's using fixtures. I also am using fixtures in my Unit tests, but they work without flaw. When running the functional tests, I get a:

NoMethodError: undefined method 'recycle!' for #<Response:0x10346be10> /test/functional/responses_controller_test.rb:10:in 'test_testing'

My functional tests, at this point, are doing nothing more than a get to the index action. Example:

setup do
  @response = responses(:one)
end

test "testing" do
  get :index
  assert true
end

My TestHelper class does include all fixtures, so the Responses fixtures are definitely loading. And like I said, the fixtures work perfectly fine in Unit tests.

Any idea what might be causing this?