Rails3 Data Migration and RSpec Test

data_migration_and_test.rb

# db/migrate/20110714024435_split_author.rb
class SplitAuthor < ActiveRecord::Migration
  def self.up
    Post.where(:author=>nil).each do |p|
      author = Author.create!(:name => p.author_name,
                              :account_id => p.account_id)
      p.author = author
      p.save!
    end
  end

  def self.down
     raise ActiveRecord::IrreversibleMigration
  end
end


# spec/migrations/split_author_spec.rb
require 'spec_helper'
require File.join(File.dirname(__FILE__), "..", "..", "db", "migrate", "20110714024435_split_author")

describe SplitAuthor do
  before do
    @posts = []
    @account = Factory(:account)
    3.times do |x|
      p = Factory.build(:post, :author=>nil, :author_name=>"author#{x}", :account=>@account)
      p.save(:validate=>false)
      @posts << p
    end
  end

  describe "up" do
    it "should populate authors from existing posts" do
      expect {
        SplitAuthor.up_without_benchmarks
      }.to change{Author.count}.by(@posts.size)
      Author.all.each{|x| x.account.should == @account}
      @posts.collect(&:author).each do |a|
        Author.find_by_name(a).should_not be_nil
      end
    end
  end
end

Hi,
nice example.
I'm currently in the situtation much like this example where my migration is:
1.adding some columns to a table
2. migrating data
3. modifying the added columns, eg. not to accept nil

I surely want to run some tests on the data migrating code, but my worry is that once I have migrated past point 3, my tests will fail, as I cannot create test data after this point. My plan is to do something like this in the tests:

class SchemaMigration < ActiveRecord::base
end

run_migrate_data_test unless SchemaMigration.all.max > migration_point_3

any comments/pitfall on this?

regards
Lars

For future reference; at least as of Rails 3.2.15, running the migration is done thusly:

MigrationClass.new.up

The class must be instantiated, and the without_benchmarks method does not exist.