function testAddStructToStruct()
 {
     $v = new xmlrpcval(array('a' => new xmlrpcval('b')), 'struct');
     $r = $v->addstruct(array('b' => new xmlrpcval('c')));
     $this->assertEquals(2, $v->structsize());
     $r = $v->addstruct(array('b' => new xmlrpcval('b')));
     $this->assertEquals(2, $v->structsize());
 }