Lazy vars include shared validator

spec.js

describe('Issue', function() {
  subject(function() {
    return new Issue();
  });
  
  def('min', function() {
    return $subject.getMinPriority();
  });
  
  def('max', function() {
    return $subject.getMaxPriority();
  });
  
  describe('"Priority" field', function() {
    includeExamplesFor('Range validator', 'priority', get.variable('min'), get.variable('max'));
  });
});