preload.php

<?php
/**
 * Unit tests preload
 *
 * @package Mantle
 */

namespace Mantle\Testing;

if ( ! function_exists( __NAMESPACE__ . '\\tests_add_filter' ) ) {
	/**
	 * Adds hooks before loading WP.
	 *
	 * @see add_filter()
	 *
	 * @param string   $tag             The name of the filter to hook the $function_to_add callback to.
	 * @param callable $function_to_add The callback to be run when the filter is applied.
	 * @param int      $priority        Optional. Used to specify the order in which the functions
	 *                                  associated with a particular action are executed.
	 *                                  Lower numbers correspond with earlier execution,
	 *                                  and functions with the same priority are executed
	 *                                  in the order in which they were added to the action. Default 10.
	 * @param int      $accepted_args   Optional. The number of arguments the function accepts. Default 1.
	 * @return true
	 */
	function tests_add_filter( $tag, $function_to_add, $priority = 10, $accepted_args = 1 ): bool {
		global $wp_filter;

		if ( function_exists( 'add_filter' ) ) {
			add_filter( $tag, $function_to_add, $priority, $accepted_args );
		} else {
			$idx = _test_filter_build_unique_id( $tag, $function_to_add );

			// phpcs:ignore WordPress.WP.GlobalVariablesOverride
			$wp_filter[ $tag ][ $priority ][ $idx ] = [
				'function'      => $function_to_add,
				'accepted_args' => $accepted_args,
			];
		}

		return true;
	}
}

if ( ! function_exists( __NAMESPACE__ . '\\_test_filter_build_unique_id' ) ) {
	/**
	 * Generates a unique function ID based on the given arguments.
	 *
	 * @see _wp_filter_build_unique_id()
	 *
	 * @param string   $tag      Unused. The name of the filter to build ID for.
	 * @param callable $function The function to generate ID for.
	 * @return string Unique function ID for usage as array key.
	 */
	function _test_filter_build_unique_id( $tag, $function ): ?string {
		if ( is_string( $function ) ) {
			return $function;
		}

		if ( is_object( $function ) ) {
			// Closures are currently implemented as objects.
			$function = [ $function, '' ];
		} else {
			$function = (array) $function;
		}

		if ( is_object( $function[0] ) ) {
			// Object class calling.
			return spl_object_hash( $function[0] ) . $function[1];
		}

		if ( is_string( $function[0] ) ) {
			// Static calling.
			return $function[0] . '::' . $function[1];
		}

		return null;
	}
}