In order to pass this test you must create a sitemap.xml file for your website. Some of the best practices are listed below:

• It is strongly recommended that you place your sitemap at the root directory of your website: http://yourwebsite.com/sitemap.xml But in some situations, you may want to produce different sitemaps for different paths on your site (e.g., security permission issues)
• Sitemaps should be no larger than 10MB (10,485,760 bytes) and can contain a maximum of 50,000 URLs. This means that if your site contains more than 50,000 URLs or your sitemap is bigger than 10MB, you must create multiple sitemap files and use a Sitemap index file
• All URLs listed in the sitemap must reside on the same host as the sitemap. For instance, if the sitemap is located at http://www.yourwebsite.com/sitemap.xml, it can't include URLs from http://subdomain.yourwebsite.com
• Once you have created your sitemap, let search engines know about it by submitting directly to them, pinging them, or adding the sitemap location to your robots.txt file
• Sitemaps can be compressed using gzip, reducing bandwidth consumption

sitemap.xml example:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
 <loc>http://www.yourwebsite.com</loc>
 <lastmod>2013-01-01</lastmod>
 <changefreq>weekly</changefreq>
 <priority>0.9</priority>
</url>
<url>
 <loc>http://www.yourwebsite.com/articles/100</loc>
 <changefreq>weekly</changefreq>
</url>
<url>
 <loc>http://www.yourwebsite.com/articles/101</loc>
 <lastmod>2013-01-02</lastmod>
 <changefreq>weekly</changefreq>
</url>
<url>
 <loc>http://www.yourwebsite.com/articles/102</loc>
 <lastmod>2013-01-02T13:00:12+00:00</lastmod>
 <priority>0.5</priority>
</url>
</urlset>

In order to pass this test you must consider using a 301 re-write rule in your .htaccess file so that both addresses (http://example.com and http://www.example.com) resolve to the same URL.
- If you want to redirect http://www.example.com to http://example.com, you can use this:

RewriteCond %{HTTP_HOST} ^www\.example\.com$
RewriteRule ^/?$ "http\:\/\/example\.com\/" [R=301,L]

- If you want to redirect http://example.com to http://www.example.com, you can use this:

RewriteCond %{HTTP_HOST} !^www.example.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]

Note that you must put the above lines somewhere after RewriteEngine On line.