old_contents: // require all modules ending in ".tests.ts" from source and all subdirectories
  
  var testsContext = require.context('./source', true, /\.tests\.js$/);
  testsContext.keys().forEach(testsContext);
  
new_contents: require('core-js/es6');
  require('core-js/es7/reflect');
  
  // require all modules ending in ".tests.ts" from source and all subdirectories
  
  var testsContext = require.context('./source', true, /\.tests\.js$/);
  testsContext.keys().forEach(testsContext);
  
subject: Include polyfills and shims required for testing.