Pantheon site environment base URL logic

settings.php

if (isset($_SERVER['PANTHEON_ENVIRONMENT'])) {
  switch ($_SERVER['PANTHEON_ENVIRONMENT']) {
    case 'test':
      $base_url = 'http://test-example.gotpantheon.com';  // NO trailing slash!
      break;
    case 'dev':
      $base_url = 'http://dev-example.gotpantheon.com';  // NO trailing slash!
      break;
    case 'live':
      $base_url = 'http://www.example.com';  // NO trailing slash!
      break;
  }
}