tax_query not working

Question

I have tried using the id, slug, name, and take the tax_query as an array of arrays but still it will output all the posts from that post type.

Here's my custom taxonomy, 'Event Specific':

function theme_event_category(){
    $labels = array(
    'name' => 'Event Specifics',
    'singular_name'=> 'Specific',
    'search_items' => 'Search Event Specifics',
    'all_items' => 'All Event Specifics',
    'parent_item' => 'Parent Event Specific',
    'parent_item_colon' => 'Parent Colon:',
    'edit_item' => 'Edit Specific Item',
    'update_item' => 'Update Specific Item',
    'add_new_item' => 'Add New Event Specific',
    'new_item_name' => 'New Specific Item',
    'menu_name' => 'Event Specific'
);

$args = array(
    'hierarchical' => false,
    'labels' => $labels,
    'show_ui' => true,
    'show_admin_column' => true,
    'query_var' => true,
    'rewrite' => array('slug' => 'event')
);

register_taxonomy('event_specific', 'event', $args  );

}
add_action('init', 'theme_event_category');

Here's my query, that should only output the 'Main Event' tag from the 'Event Specific' taxonomy:

$quertest = array(
        'post_type'             =>  'event',
        'posts_per_page'        =>  1,
        'tax_query'             =>  array(array('event_specific', 'slug', 'main-event')),
);

 $upcoming_events = new WP_Query( $quertest );

<?php while ( $upcoming_events->have_posts() ) : $upcoming_events->the_post();
    echo 'Title: ';
    the_title();
?>

Answer 1

In your tax_query array you need to add the keys as well as the values.

So...

'tax_query' => array(
    array(
        'taxonomy' => 'event_specific', 
        'field' => 'slug', 
        'terms' => 'main-event'
     )
)