Check whether sessions work in php

checkSession.php

<?php

error_reporting( E_ALL );
ini_set( 'display_errors', 1);

define('TEST_KEY', 'test');
define('TEST_VAL', 'test42');

$fileName = basename(__FILE__);

if(!isset($_GET['action'])){
	die('Param is missing. Look at the <a href="https://gist.github.com/mallardduck/3f199ccf0a8ce270329bc624de6b26cf">source</a>.');
}

switch($_GET['action']) {
	case "start":
		if(session_start() && $_SESSION[TEST_KEY] = TEST_VAL){
			echo 'Test session probably started successfully. Go <a href="' . $fileName . '?action=check">check</a>!</br>';
		}else{
			echo 'Starting a test session seems to have failed. Go <a href="' . $fileName . '?action=check">check</a>!</br>';
		}
		echo 'And some additional information:</br>';
		echo 'session.save_path : ' . ini_get('session.save_path') . '</br>';
		echo 'session.cookie_path : ' . ini_get('session.cookie_path') . '</br>';
		echo 'session.name : ' . ini_get('session.name') . '</br>'; 
		break;
	case "delete":
		if(session_start() && (isset($_SESSION[TEST_KEY]) && $_SESSION[TEST_KEY] === TEST_VAL)){
			$_SESSION = array();
			if (ini_get("session.use_cookies")) {
				$params = session_get_cookie_params();
				setcookie(session_name(), '', time() - 42000, $params['path'], $params['domain'], $params['secure'], $params['httponly'] );
			}
			session_destroy();
			echo "Test session deleted.";
		}else{
			echo 'Sessions don\'t seem to work, or the test session wasn\'t started yet.';
			echo 'To start a test session. Go <a href="' . $fileName . '?action=start">check</a>!</br>';
		}
		break;
	case "check":
		session_start();
		if(isset($_SESSION[TEST_KEY]) && $_SESSION[TEST_KEY] === TEST_VAL){
			echo "Sessions seem to work. :-)";
		}else{
			echo "Sessions don't seem to work. :-(";
		}
		break;
	default: die("Hey, I told you to look at the source. :P");
}