Hi @shafigh,
First of all, you are wrongly nesting the velocity and html macros, html must be used as child of velocity. If you revert them, then you will notice different errors and the first one would be that the search query in $xwiki.search("space:Tests") is wrong. Please look at https://extensions.xwiki.org/xwiki/bin/view/Extension/Query%20Module.
Hope it helps,
Alex