Can you please be more specific? What does it mean that "the methods failed"?

I think AR objects look for these methods, take a look on what I do to get this error:

spec_helper.rb :

ENV["RAILS_ENV"] = "test"
require File.expand_path(File.dirname(__FILE__) + "/../config/environment")
require 'spec'
require 'spec/rails'
require 'rspec_rails_mocha'
require File.expand_path(File.dirname(__FILE__) + "/blueprints")

Spec::Runner.configure do |config|
...

bank_account_spec.rb (the spec where I use mock_model)

require File.dirname(__FILE__) + '/../spec_helper'

describe BankAccount do

  def make_bank_account(attributes = {})
    account = mock_model(Account)
    @bank_account = BankAccount.make(:account => account)
  end
  ....

As you can see, I'm using mock_model to mock an association in my bank_account model spec. And when I run it these errors appear:

undefined method `blank?' for "#":Account

If I stub blank? I get is_a? and collect undefined.

In this line @bank_account = BankAccount.make(:account => account) , I'm calling the machinist method and send account mock that should behave like a AR object and pass the ID to BankAccount association but get the above errors.