old_contents: var mock = require('./mock');
  var JSONOutput = require('../lib/output/json');
  
  describe('JSON Output', function() {
  
      describe('Sample book', function() {
          var output;
  
          before(function() {
              return mock.outputDefaultBook(JSONOutput)
              .then(function(_output) {
                  output = _output;
              });
          });
  
          it('should correctly generate a README.json', function() {
              output.should.have.file('README.json');
          });
  
      });
  
      describe('Multilingual Book', function() {
          var output;
  
          before(function() {
              return mock.outputBook(JSONOutput, {
                  'LANGS.md': '# Languages\n\n'
                      + '* [en](./en)\n'
                      + '* [fr](./fr)\n\n',
                  'en/README.md': '# Hello',
                  'fr/README.md': '# Bonjour'
  
              })
              .then(function(_output) {
                  output = _output;
              });
          });
  
          it('should correctly generate a README.json for each language', function() {
              output.should.have.file('en/README.json');
              output.should.have.file('fr/README.json');
          });
  
          it('should correctly add languages list to all json', function() {
              var jsonFR = require(output.resolve('fr/README.json'));
              var jsonEN = require(output.resolve('en/README.json'));
  
              jsonFR.should.have.property('languages')
                  .with.property('list').with.lengthOf(2);
              jsonEN.should.have.property('languages')
                  .with.property('list').with.lengthOf(2);
          });
  
          it('should correctly generate a README.json for the whole book', function() {
              output.should.have.file('README.json');
  
              var json = require(output.resolve('README.json'));
  
              json.should.have.property('languages')
                  .with.property('list').with.lengthOf(2);
          });
      });
  });
  
  
new_contents: var mock = require('./mock');
  var JSONOutput = require('../lib/output/json');
  
  describe('JSON Output', function() {
  
      describe('Sample book', function() {
          var output;
  
          before(function() {
              return mock.outputDefaultBook(JSONOutput)
              .then(function(_output) {
                  output = _output;
              });
          });
  
          it('should correctly generate a README.json', function() {
              output.should.have.file('README.json');
          });
  
      });
  
      describe('Multilingual Book', function() {
          var output;
  
          before(function() {
              return mock.outputBook(JSONOutput, {
                  'LANGS.md': '# Languages\n\n'
                      + '* [en](./en)\n'
                      + '* [fr](./fr)\n\n',
                  'en/README.md': '# Hello',
                  'fr/README.md': '# Bonjour'
  
              })
              .then(function(_output) {
                  output = _output;
              });
          });
  
          it('should correctly generate a README.json for each language', function() {
              output.should.have.file('en/README.json');
              output.should.have.file('fr/README.json');
          });
  
          it('should correctly add languages list to all json', function() {
              var jsonFR = require(output.resolve('fr/README.json'));
              var jsonEN = require(output.resolve('en/README.json'));
  
              jsonFR.should.have.property('languages')
                  .with.property('list').with.lengthOf(2);
              jsonEN.should.have.property('languages')
                  .with.property('list').with.lengthOf(2);
          });
  
          it('should correctly generate a README.json for the whole book', function() {
              output.should.have.file('README.json');
              var json = require(output.resolve('README.json'));
  
              json.book.language.should.equal('en');
  
              json.should.have.property('languages')
                  .with.property('list').with.lengthOf(2);
          });
      });
  });
  
  
subject: Add test for main language in json output