old_contents: /*global describe, before, it, assert, MusicPlayer */
  describe('Music player in browser', function () {
      before(function () {
          this.musicPlayer = new MusicPlayer();
      });
  
      describe('Instance', function () {
          it('should be made MusicPlayer instance', function () {
              assert(this.musicPlayer instanceof MusicPlayer === true);
          });
      });
  
      describe('#loadMusic()', function () {
          it('should load music file', function () {
              // TODO
          });
      });
  
      describe('#isMusicFile()', function () {
          it('should is music file', function () {
              // TODO
          });
      });
  
      describe('#play()', function () {
          it('should play sound', function () {
              // TODO
          });
      });
  
      describe('#stop()', function () {
          it('should stop sound', function () {
              // TODO
          });
      });
  
      describe('#rewind()', function () {
          it('should rewind sound', function () {
              // TODO
          });
      });
  
      describe('#forward()', function () {
          it('should forward sound', function () {
              // TODO
          });
      });
  });
  
new_contents: /*global describe, before, it, assert, MusicPlayer */
  describe('Music player in browser', function () {
      var musicPlayer = null;
  
      before(function () {
          musicPlayer = new MusicPlayer();
      });
  
      describe('Instance', function () {
          it('should be made MusicPlayer instance', function () {
              assert(musicPlayer instanceof MusicPlayer === true);
          });
      });
  
      describe('#loadMusic()', function () {
          it('should load music file', function () {
              // TODO
          });
      });
  
      describe('#isMusicFile()', function () {
          it('should be file is music file format', function () {
              var types = {
                  mp3: 'audio/mp3',
                  wav: 'audio/wav',
                  ogg: 'audio/ogg',
                  m4a: 'audio/x-m4a',
                  wma: 'audio/x-ms-wma'
              };
  
              for (var i in this.types) {
                  assert(musicPlayer.isMusicFile(types[i]) === true);
              }
          });
      });
  
      describe('#play()', function () {
          it('should play sound', function () {
              // TODO
          });
      });
  
      describe('#stop()', function () {
          it('should stop sound', function () {
              // TODO
          });
      });
  
      describe('#rewind()', function () {
          it('should rewind sound', function () {
              // TODO
          });
      });
  
      describe('#forward()', function () {
          it('should forward sound', function () {
              // TODO
          });
      });
  });
  
subject: Add test for isMusicFile()