/**
  * test sanitize with empty input
  */
 function testStringVR_sanitize_empty()
 {
     $svr = new StringValidationRule('A_String', null, null);
     $this->assertEquals('', $svr->sanitize('testStringVR_sanitize_empty', null));
     $this->assertEquals('', $svr->sanitize('testStringVR_sanitize_empty', ''));
 }