rspec test result from csv.read mocking file

I'm using ruby 1.9 and I'm trying to do BDD. My first test 'should read in the csv' works, but the second where I require a file object to be mocked doesn't.

Here is my model spec:

require 'spec_helper'

describe Person do
  describe "Importing data" do
    let(:person) { Person.new }

    let(:data) { "title\tsurname\tfirstname\t\rtitle2\tsurname2\tfirstname2\t\r"}
    let(:result) {[["title","surname","firstname"],["title2","surname2","firstname2"]] }

    it "should read in the csv" do
      CSV.should_receive(:read).
        with("filename", :row_sep => "\r", :col_sep => "\t")
      person.import("filename")
    end

    it "should have result" do
      filename = mock(File, :exists? => true, :read => data)
      person.import(filename).should eq(result)
    end
  end
end

Here is the code so far:

class Person < ActiveRecord::Base
  attr_accessor :import_file

  def import(filename)
    CSV.read(filename, :row_sep => "\r", :col_sep => "\t")
  end
end

I basically want to mock a file so that when the CSV method tries to read from the file it returns my data variable. Then I can test if it equals my result variable.