  Variants of the must testing approach have been successfully applied in
service oriented computing for analysing the compliance between (contracts
exposed by) clients and servers or, more generally, between two peers. It has
however been argued that multiparty scenarios call for more permissive notions
of compliance because partners usually do not have full coordination
capabilities. We propose two new testing preorders, which are obtained by
restricting the set of potential observers. For the first preorder, called
uncoordinated, we allow only sets of parallel observers that use different
parts of the interface of a given service and have no possibility of
intercommunication. For the second preorder, that we call individualistic, we
instead rely on parallel observers that perceive as silent all the actions that
are not in the interface of interest. We have that the uncoordinated preorder
is coarser than the classical must testing preorder and finer than the
individualistic one. We also provide a characterisation in terms of decorated
traces for both preorders: the uncoordinated preorder is defined in terms of
must-sets and Mazurkiewicz traces while the individualistic one is described in
terms of classes of filtered traces that only contain designated visible
actions and must-sets.
