public function offsetUnsetAtEnd()
{
$str = new String('www.müller.com');
unset($str[$str->length() - 1]);
$this->assertEquals(new String('www.müller.co'), $str);
}
public function stringTestChar()
{
$s = new String('Übercoder', 'iso-8859-1');
$this->assertTrue(isset($s[0]));
$this->assertTrue(isset($s[$s->length() - 1]));
$this->assertFalse(isset($s[$s->length()]));
$this->assertFalse(isset($s[-1]));
}