Original Article

Formal Aspects of Computing

, Volume 24, Issue 4, pp 727-748

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Probabilistic may/must testing: retaining probabilities by restricted schedulers

  • Sonja GeorgievskaAffiliated withDepartment of Mathematics and Computer Science, Eindhoven University of Technology Email author 
  • , Suzana AndovaAffiliated withDepartment of Mathematics and Computer Science, Eindhoven University of Technology


This paper considers the probabilistic may/must testing theory for processes having external, internal, and probabilistic choices. We observe that the underlying testing equivalence is too strong and distinguishes between processes that are observationally equivalent. The problem arises from the observation that the classical compose-and-schedule approach yields unrealistic overestimation of the probabilities, a phenomenon that has been recently well studied from the point of view of compositionality, in the context of randomized protocols and in probabilistic model checking. To that end, we propose a new testing theory, aiming at preserving the probability information in a parallel context. The resulting testing equivalence is insensitive to the exact moment the internal and the probabilistic choices occur. We also give an alternative characterization of the testing preorder as a probabilistic ready-trace preorder.


Probabilistic may/must testing Restricted schedulers Ready-trace equivalence