hook_node_view_alter not working
After researching more examples out there in the Web, I've finally managed to make this work, however I'm still not sure why it was not working before...

Working code:

&lt;?php

/**
 * @file
 * Implementation of hook_entity_view_alter();
 */

function test_module_entity_view_alter($entity, $type, $view_mode) {
    drupal_set_message(t('Hello world!'));
}


Moving on to further modifications. Thanks everyone!