anchor.diff:  
     const $kataPage = $('#kata-page');
     const $reviewPage = $('#review-page');
  +
  +  const inTestPage = $kataPage.length !== 0;
   
     cd.setReviewData = (version, id, groupId, avatarName, avatarIndex, wasIndex, nowIndex, filename) => {
       // Called only from app/views/kata/_traffic_lights.html.erb
  
positive.code:       }));
      }
    };
  
    const inTestPage = $kataPage.length !== 0;
  
    // - - - - - - - - - - - - - - - - - - - - - - - -
  
  
negative.code:          nowIndex:nowIndex,
           filename:filename
      };
      fadeIntoReviewPage();
      setupAvatar(avatarName, avatarIndex);
      setupButton('resume', () => fadeIntoKataPage(() => { // [1]
        cd.kata.editor.refocus();
      }));
      setupButton('revert', () => fadeIntoKataPage(() => { // [1]
        cd.revert({ id:param.id, now_index:param.nowIndex });
      }));
      setRevertButtonTip();
      refresh();
    };
  
    // - - - - - - - - - - - - - - - - - - - - - - - -
  
    const fadeIntoReviewPage = () => {
      $kataPage.fadeOut('fast', () => {
        $reviewPage.fadeIn('fast');
      });
    };
  
    const fadeIntoKataPage = (onComplete) => {
      $reviewPage.fadeOut('fast', () => {
        $kataPage.fadeIn('fast', () => {
          onComplete();
        });
      });
    };
  
    // - - - - - - - - - - - - - - - - - - - - - - - -
  