title: rails rspec expects fails for custom validations
body: <p>I get this error when running my rspec expects with custom validators.</p>
  
  <pre><code>expect {@ua.save!}.to  raise_error(ActiveRecord::RecordInvalid,'Validation failed: This question is no longer active')
  </code></pre>
  
  <p>fails with</p>
  
  <pre><code>expected ActiveRecord::RecordInvalid with "Validation failed: This question is no longer active", got #&lt;ActiveRecord::RecordInvalid: Validation failed: This question is no longer active.&gt; with backtrace:
  </code></pre>
  
  <p>This only seems to be problem with my custom validations. 
  See this model:</p>
  
  <pre><code>class UserAnswer &lt; ActiveRecord::Base
    belongs_to :user
    belongs_to :question
    validate :questionIsActive?
  
    private
  
    def questionIsActive?
      errors.add(:base, "This question is no longer active.") if !self.question.is_active?
    end
  end
  </code></pre>
  
  <p>Using:
  Rails 3.2.11
  Rspec-rails 2.12.2</p>