public function testMultipleUuidGeneration() {
		$check = array();
		$count = 50;
		$pattern = "/^[a-f0-9]{8}-[a-f0-9]{4}-4[a-f0-9]{3}-[8-9a-b][a-f0-9]{3}-[a-f0-9]{12}$/";

		for ($i = 0; $i < $count; $i++) {
			$result = String::uuid();
			$match = preg_match($pattern, $result);
			$this->assertTrue($match);
			$this->assertFalse(in_array($result, $check));
			$check[] = $result;
		}
	}