Verifies that the datepicker can be localized.
locale_library_info_alter()
public function testLibraryInfoAlter() {
drupal_add_library('system', 'ui.datepicker');
$scripts = drupal_get_js();
$this
->assertTrue(strpos($scripts, 'locale.datepicker.js'), 'locale.datepicker.js added to scripts.');
}