Creates a fresh installation of Drupal with tables in a prefix simpletest* and has a virtual browser.
class ExampleTestCase extends DrupalWebTestCase {
  public static function getInfo() {
    return array(
      'name' => 'Name',
      'description' => 'Description',
      'group' => 'Group',
    );
  }
  public function setUp() {
    parent::setUp('example_module');
  }
}
          
        Doesn't create tables, and is lighter and faster.
class ExampleUnitTestCase extends DrupalUnitTestCase {
  public static function getInfo() {
    return array(
      'name' => 'Name',
      'description' => 'Description',
      'group' => 'Group',
    );
  }
  public function setup() {
    drupal_load('module', 'example_module');
    parent::setUp();
  }
}