A simple plugin for adding filters/code for plugin testing.

site-testing.php

<?php
/**
 * Plugin Name:          Site Testing
 * Plugin URI:           https://gist.github.com/afragen/a30b7766d8eb1aa22018130dfd5034f4
 * Description:          This plugin is used for site testing.
 * Version:              0.4
 * Author:               Andy Fragen
 * License:              MIT
 * Requires at least:    5.2
 * Requires PHP:         7.1
 * Gist Plugin URI:      https://gist.github.com/afragen/a30b7766d8eb1aa22018130dfd5034f4
 */


/**
 * Git Updater filter testing.
 */

add_filter(
	'gu_override_dot_org',
	function ( $overrides ) {
		return array_merge(
			$overrides,
			[
				'wp-simple-calendar/wp-simple-calendar.php',
			// 'the-events-calendar/the-events-calendar.php',
			]
		);
	}
);

// Test for entering negative number, absint() should convert to positive integer.
// Default return is 1.
add_filter(
	'gu_number_rollbacks',
	function() {
		return -2;
	}
);

// Fix for mailgun and GitHub Updater.
// add_filter(
// 	'gu_unset_auth_header',
// 	function ( $hosts ) {
// 		return array_merge( $hosts, [ 'api.mailgun.net' ] );
// 	}
// );

// add_filter( 'github_updater_disable_wpcron', '__return_true' );

/**
 * Git Remote Updater filter testing.
 */

add_filter(
	'git_remote_updater_remove_site_data',
	function () {
		return [ 'caldera-forms' ];
	}
);

// Shorten transient timeout for testing, default is 5 minutes.
add_filter(
	'git_remote_updater_repo_transient_timeout',
	function () {
		return 5;
	}
);


/**
 * WP Debugging filter testing.
 */

add_filter(
	'wp_debugging_add_constants',
	function ( $added_constants ) {
		$my_constants = [
			'ITSEC_DEBUG' => [ 'value' => 'true' ],
		];

		return array_merge( $added_constants, $my_constants );
	},
	10,
	1
);


/**
 * Add CPT Featured Image WP Recipe testing.
 */

add_filter(
	'acfi_wprm_cpt_slug',
	function ( $cpt_slug ) {
		// $cpt_slug = 'test';
		return $cpt_slug;
	}
);

/**
 * Miscellaneous.
 */

// Fixes https://core.trac.wordpress.org/ticket/25239.
add_action(
	'init',
	function () {
		$wp_version = get_bloginfo( 'version' );
		if ( defined( 'WP_CLI' ) && WP_CLI
			&& version_compare( $wp_version, '5.5-RC2', '<' )
		) {
			$_SERVER['SERVER_NAME'] = isset( $_SERVER['SERVER_NAME'] ) ? $_SERVER['SERVER_NAME'] : parse_url( network_home_url(), PHP_URL_HOST );
		}
	}
);