moved get_guid to System::createGUID

tests/src/Core/SystemTest.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Friendica\Test\src\Core;
+
+use Friendica\Core\System;
+use PHPUnit\Framework\TestCase;
+
+class SystemTest extends TestCase
+{
+	private function assertGuid($guid, $length)
+	{
+		$this->assertRegExp("/^[a-z0-9]{" . $length . "}?$/", $guid);
+	}
+
+	function testGuidWithoutParameter()
+	{
+		$guid = System::createGUID();
+		$this->assertGuid($guid, 16);
+	}
+
+	function testGuidWithSize() {
+		$guid = System::createGUID(20);
+		$this->assertGuid($guid, 20);
+	}
+}