How to test the site in maintenance mode in Drupal 6 and Drupal 7

How to test the site in maintenance mode in Drupal 6 and Drupal 7? During many instances there are occasions where you would like to take the Drupal site offline before your testers run through the various testing procedures.

To take the site offline,

In Drupal 6:
Login as admin and
Open site configuration --> site maintenance.

In Drupal 7:
Login as admin and
Open configuration --> maintenance mode.

Then select “Offline” / “Maintenance” mode, from the options shown.

You will also be able to set a message to be shown to those who visit the site while the site is offline. If the site is set to 'Online' all visitors are allowed to browse your site normally. But when the site is under maintenance mode, all the visitors should be able to see the offline message set by administrator. When the site is offline only users with the "administer site configuration" permission will be able to access your site.

Site maintenance

Site status:
Online
Off-line

When set to "Online", all visitors will be able to browse your site normally. When set to "Off-line", only users with the "administer site configuration" permission will be able to access your site to perform maintenance; all other visitors will see the site off-line message configured below. Authorized users can log in during "Off-line" mode directly via the user login page.