public function testValueOf()
 {
     $this->assertEquals('true', $this->object->valueOf(true));
     $this->assertEquals('false', $this->object->valueOf(false));
     $this->assertEquals('0', $this->object->valueOf(0));
     $this->assertEquals('2120', $this->object->valueOf(2120));
     $this->assertEquals('2120.32', $this->object->valueOf(2120.32));
     $this->assertEquals('2120', $this->object->valueOf('2120'));
     $this->assertEquals('', $this->object->valueOf(''));
     $this->assertEquals('', $this->object->valueOf(null));
 }