(sanitize-post "<div aa=\"\">dd</div>") .............................. [ FAIL]
    expected ("((div (@) \"dd\"))" "((div (@ (aa \"\")) \"dd\"))") but got ("((div (@) \"dd\"))" "((div (@ (aa \"()\")) \"dd\"))")

(sanitize-post "<div data-widget-s11n=\"\">dd</div>") ................ [ FAIL]
    expected ("()" "((div (@ (data-widget-s11n \"\")) \"dd\"))") but got ("()" "((div (@ (data-widget-s11n \"()\")) \"dd\"))")