Forum: RSpec isolating controller tests from models

This is a rehash of a question I posed at:
  http://stackoverflow.com/questions/9952317/isolati...
The basic question: If I have a FoosController and a Foo model, can I
run FoosController rspec tests without creating the foos database table?
I haven't found a good way to avoid it.

Consider this simple controller:

    # file: app/controllers/foos_controller.rb
    class FoosController < ApplicationController
      respond_to :json
      def create
        @foo = Foo.create(params[:foo])
        respond_with @foo
      end
    end

In my RSpec tests, I can do

    @foo = mock_model("Foo")
    Foo.stub(:create) { @foo }
    post :create, :format => :json

... but that fails in the call to respond_with @foo, because
ActionController calls @foo.has_errors? which in turn hits the database
to look up column names.  I could stub out has_errors?, but that means
that I'm reaching into the internals of the system -- probably not a
good idea for a test suite.

If the answer to my question "can I do controller testing without
creating the underlying database tables?" is 'no', then I'll accept that
(with regret).  But I'd rather hear that it is somehow possible.

- ff