问如何在rspec测试中创建时态表

EN

class Address < ActiveRecord::Base
  attr_accessible :street, :zip
end

module Addressable
  def self.included(base)
    base.class_eval <<-CLASS_METHODS
          belongs_to :address
          validates :address, presence: true
    CLASS_METHODS
  end
end

require 'spec_helper'
describe 'Addressable' do

  subject do
    class OtherModel < ActiveRecord::Base
      include Addressable
    end
  end

  before(:all) do
    connection = ActiveRecord::Base.connection
    connection.create_table :othermodels do |t|
      t.references :address
    end
  end

  after(:all) do
    connection.drop_table :othermodels
  end

  it "should validate presence of address"do
    should validate_presence_of(:address)
  end

  it "should belongs to address" do
should belong_to :continent
  end
end

 1) Addressable should validate presence of address
   Failure/Error: should validate_presence_of(:address)
   NoMethodError:
     undefined method `address=' for OtherModel(Table doesn't exist):Class