shortcodes output before content [duplicate]

Shortcode callbacks have to return, not output. So use the following:

function test() {
    return '-TEST-';
}
add_shortcode( 'testshortcode', 'test' );

More info: http://codex.wordpress.org/Shortcode_API

If you have to use echo you can also do it this way(useful if there’s a lot of markup & it’s difficult working with strings)-

function test() {
    ob_start();
    echo '-TEST-';
    return ob_get_contents();
}
add_shortcode( 'testshortcode', 'test' );