test_plugin.php

<?php
    /*
    Plugin Name: Test Plugin
    Plugin URI:
    Description: A test example plugin
    Author: R. W. Duerr
    Version: 1.0.0
    Author URI:
    */

    $loader = require __DIR__.'/vendor/autoload.php';
    use TestPlugin\TestPlugin_Class;
    use TestPlugin\UtilityFunctions;
    use TestPlugin\WPDataSource;

    //disable external access
    if (!defined('ABSPATH')) {
        die('Invalid Usage. Use through the wordpress plugin API.');
    }

    //init the plugin variables (inside this namespace)
    define('TestPlugin\\TestPlugin_DIR', dirname(__FILE__));
    define('TestPlugin\\TestPlugin_URL', plugins_url('', __FILE__));
    define('TestPlugin\\TestPlugin_SRC_DIR', TestPlugin\TestPlugin_DIR.DIRECTORY_SEPARATOR.'includes'.DIRECTORY_SEPARATOR.'TestPlugin');

    $allFilesPresent = TestPlugin_Class::do_incomplete_plugin_check();

    if (!$allFilesPresent) {
        // Warn if the plugin install is incomplete - can happen if WP crashes (e.g. out of disk space) when upgrading the plugin
        add_action('all_admin_notices', array('TestPlugin\\TestPlugin_Class', 'incomplete_install_warning'));
    } else {
        //pass in this file, as some hook require the SOURCE entry point file for this plugin to work
        $test_plugin_class = new TestPlugin_Class(__FILE__);
    }