Wordpress shortcodes not rendering - php

Question

I'm attempting to add a shortcode wordpress sites using a custom plugin. No matter how I try to register or call this, the shortcode does not seem to render.
I am using the default 2020 theme from Wordpress to test this.
This is the code that adds the shortcode:
add_shortcode(
'test',
function () {
return 'test output';
}
);
If I manually check this on the template:
var_dump(shortcode_exists('test'));
the following is generated on a page load:
boolean true
However, if the following is added to the page content, it does not load:
[test]
I have also added the following to the theme functions.php
add_filter( 'widget_text', 'do_shortcode' );
However, as this is not within a widget (just post text) I did this to eliminate this possibility. It did not help.
Edit:
I also added the following to the page:
do_shortcode(['test']);
This produces the required output.
Every single tutorial does the above, pretty much verbatim.
What am I missing?
To be clear: Using [test] in content to show the shortcode inside post body content is the required behaviour.

Answer 1

Try to change the test name, suddenly it is reserved, and secondly, print the entire shortcode
print do_shortcode('[mytest]'); // [test]
<?php
/*
Plugin Name: Test
Description: La la la fa
Version: 0.1.0
*/
function question($attrs, $content = null) {
return '???';
}
add_shortcode('question', 'question');
add_action('init', function() {
d(do_shortcode('Are you sure [question]'));
});
Methods to output content with handling of shortcodes
the_content();
get_the_content();
apply_filters('the_content', $post->post_content);
Example:
add_action('init', function() {
d(apply_filters('the_content', 'Are you sure [question]')); // $post->post_content
});

Answer 2

This was a custom testing template, and the content of a post is not automatically parsed.
I've actually created a huge amount of custom meta data per post that I was arranging and presenting outside of the content, so I had used the $post->post_content property.
To be clear... $post->post_content is not parsed, the_content() is.
Things now work.
This is a good gotcha.