added helper functions which are injected into every test

tests/util.php

@@ -0,0 +1,12 @@
+<?php declare(strict_types=1);
+
+use parkdown\Parkdown;
+
+function createTest(string $source, string $target) : array {
+	$strip = function(string $string) : string {
+		return trim(preg_replace("/\s+/", "", $string));
+	};
+
+	$parkdown = new Parkdown($source);
+	return [$strip($target), $strip($parkdown->html())];
+}