Lazy vars variable shadowing

spec.js

describe('Article', function() {
  subject(function() {
    return Article.create({ title: 'BDD lazy vars' });
  });
  
  its('status', () => is.expected.to.equal('draft'));
  
  describe('changes history', function() {
    subject(function() {
      return $subject.changes(); // $subject refers to parent subject, i.e. created article
    });
    
    it('is empty by default', function() {
      expect($subject).to.be.empty; // $subject refers to local subject, i.e. article changes
    });
  });
});