public function execute()
 {
     $s = new Stringizer($this->getValue());
     if ($s->endsWith($this->suffix)) {
         return $this->getValue();
     } else {
         return $this->getValue() . $this->suffix;
     }
 }
 public function testValidStartsWith()
 {
     $s = new Stringizer("文字列のそれ");
     $this->assertEquals(true, $s->endsWith("れ"));
     $s = new Stringizer("文字列のそれ");
     $this->assertEquals(false, $s->endsWith("れれれれ"));
     $s = new Stringizer("Fizz Buzz");
     $this->assertEquals(true, $s->endsWith("zz"));
 }