title: Why am I asked to run 'rake db:migrate RAILS_ENV=test'?
body: <p>On Rails 4.0.0.rc1, Ruby 2.0.0, after I run a migration, I see the following error when I try to run a test through <code>rspec</code>:</p>
  
  <blockquote>
    <p>/Users/peeja/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:376:in
    `check_pending!': Migrations are pending; run 'rake db:migrate
    RAILS_ENV=test' to resolve this issue.
    (ActiveRecord::PendingMigrationError)</p>
  </blockquote>
  
  <p>That doesn't seem right. No one migrates their test database, do they? They <code>db:test:prepare</code> it, which—to be fair—I've forgotten to do. So I run <code>rake db:test:prepare</code> and run my <code>rspec</code> command again…and see the same error.</p>
  
  <p>If I actually <code>rake db:migrate RAILS_ENV=test</code>, the error does in fact go away.</p>
  
  <p>What's going on? Is this new in Rails 4?</p>