public function testRegionCompare()
{
$str1 = new Str("asdfqwerty");
$str2 = new Str("qwertyasdf");
$this->assertLessThanOrEqual(-1, $str1->regionCompare(0, $str2, 0, 4));
$this->assertEquals($str1->regionCompare(0, $str2, 6, 4), 0);
$this->assertGreaterThanOrEqual(1, $str2->regionCompare(0, $str1, 0, 4));
}