/**
  * getValid does not treat '0' as empty. disallows empty values when
  * allowNull is false.
  */
 function testStringVR_getValid_Empty()
 {
     $svr = new StringValidationRule('A_String', null, '^.*$');
     $this->assertTrue($svr->isValid('testStringVR_getValid_Empty', '0'));
     $this->assertFalse($svr->isValid('testStringVR_getValid_Empty', ''));
     $this->assertFalse($svr->isValid('testStringVR_getValid_Empty', null));
     $svr->setAllowNull(true);
     $this->assertTrue($svr->isValid('testStringVR_getValid_Empty', ''));
     $this->assertTrue($svr->isValid('testStringVR_getValid_Empty', null));
 }