anchor.diff:  
   sub vcl_deliver {
     # make sure ab testing is part of the cookie on the way back out
  -  set resp.http.Set-Cookie = "ab_group=" req.http.X-AB-Group "; path=/";
  -}
  +  if (req.http.X-Added-AB-Group) {
  +    if (resp.http.Set-Cookie) {
  +      set resp.http.Set-Cookie = resp.http.Set-Cookie "; ab_group=" req.http.X-AB-Group "; path=/";
  +    }
  +    else {
  +      set resp.http.Set-Cookie = "ab_group=" req.http.X-AB-Group;
  +    }
  +  }
  +}
  
positive.code:         sprintf(buff,"%d",rand()%2 + 1);
          VRT_SetHdr(sp, HDR_REQ, "\013X-AB-Group:", buff, vrt_magic_string_end);
        }C
        # 
        if (req.http.Cookie) {
          set req.http.Cookie = req.http.Cookie ";";
        } else {
  
negative.code:     # Rewrite top-level wordpress requests to /blog/
      set req.url = regsub(
          req.url,
          "^/(learn|policy|layout/footer_page_list|layout/homepage_post_list|layout/navigation_page_list)",
          "/blog/\1"
      );
      <% end %>
  