An XML sitemap or simply sitemap is an XML file containing the URL's of a website. Sitemaps are important tools in letting search engines know of all content present on a site. This is more so in cases where search engines are not crawling the site well because of improper linkage or low significance. There is a module called XMLSitemap in Drupal that allows a site owner to easily set up a sitemap on a Drupal website.
Why use an XML sitemap on a Drupal website?
Sitemaps allows search engines to index the content in websites quickly. It also provides the option for the webmaster to decide which pages are to be displayed to the crawlers. XML sitemap provides an option submit the content on the site directly to search engines. Since sitemap is important from an SEO perspective its testing is equally important.
How to check whether the XML sitemap is enabled in a Drupal website?
Go to Admin -> configuration -> Modules and check whether the XML sitemap module is enabled.
How to test whether XML sitemap is working correctly?
If XML sitemap is enabled in a website, then the list of URLs will be displayed on visiting the relative url - /sitemap.xml - on the site. Do note that this name is configurable as well via the module. For better understanding, see the below screenshot.
Hope this helps. Happy testing!