Template tags are not methods of WP_Query object. They are functions.
On the other hand have_posts and the_post are methods of WP_Query.
So in your code you should use:
while ($test->have_posts()) : $test->the_post();
as you do, but then:
echo get_the_title();
echo get_the_content();
Also… if you want to echo these values, it would be much better to use the_title and the_content instead – there are some additional filters and actions fired up.