text: /**
   * Script which executes unit tests for all functions in the subsystem. 
   */
  
  const assert          = require('assert');
  const tweeter         = require('../tweeter');
  const twitterConfig   = require('../twitterConfig');
  const facebookPoster  = require('../facebookPoster');
  const facebookConfig  = require('../facebookConfig');
  
  describe('facebookPoster', function() {
    
      describe('#postOnPage', function() {
  it('should return HTTP status code 200 when the post is successful. \
  If post is unsuccessful, the only acceptable status code should be 400 \
  which means that the post is a duplicate of a recent one previously posted.', function() {
  
            var promiseFromPost = facebookPoster.postOnPage(facebookConfig.PAGE_ID, 
              "Another huge explosion in Nanyang Technological\
              University's School of Computer Science\
                and Engineering reported on 17/3/19 at 13:50",
                facebookConfig.pageAccessToken);
  
            promiseFromPost.then(function(statusCode) {
              assert.equal(statusCode, 200);
            }).catch(function(statusCode) {
              assert.equal(statusCode, 400);
            })
          });
      });
  
  });
  
  describe('tweeter', function() {
  
    describe('#postTweet', function() {
  it('should return HTTP status code 200 when the post is successful. \
  If post is unsuccessful, the only acceptable status code should be 403 \
  which means that the tweet is a duplicate of a recent one previously posted.', function() {
  
            var promiseFromTweet = tweeter.postTweet( 
              "Another huge explosion in Nanyang Technological\
              University's School of Computer Science\
                and Engineering reported on 17/3/19 at 13:50",
              twitterConfig);
  
              promiseFromTweet.then(function(statusCode) {
                  assert.equal(statusCode, 200);
              }).catch(function(statusCode) {
                  assert.equal(statusCode, 403);
              });
  
          });
      });
  });