Isolating controller tests from models

This is a rehash of a question I posed at:
ruby on rails 3 - isolating controller tests from models - Stack Overflow
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

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