// @todo ...
$relation = $osmApi->getRelation('500');
$memberRole = 'yapafo_test';
// Create a node
$node = $osmApi->addNewNode(0.1, 0.1);
$node->addTag('A yapafo.net test', 'add node');
// Add it has member to the relation
$member = new OSM_Objects_Member(OSM_Api::OBJTYPE_NODE, $node->getId(), $memberRole);
$relation->addMember($member);
$osmApi->saveChanges('A yapafo.net test');
//
// Check node exists and it's a relation's member.
//
$osmApi->removeAllObjects();
$relation = $osmApi->getRelation('500', true);
$nodes = $osmApi->getNodesByTags(array('A yapafo.net test' => 'add node'));
_assert($nodes != null);
$members = $relation->findMembersByTypeAndRole(OSM_Api::OBJTYPE_NODE, $memberRole);
_assert($members != null);
// remove this new member and delete the created node
foreach ($members as $member) {
    $relation->removeMember($member);
}
$osmApi->saveChanges('A yapafo.net test');
// delete the created node
$osmApi->removeAllObjects();
$relation = $osmApi->getRelation('500', true);
foreach ($members as $member) {
    $osmApi->getNode($member->getRef())->delete();
}
$osmApi->saveChanges('A yapafo.net test');