  The global testing problem studied in this paper is to seek a definite answer
to whether a system of concurrent black-boxes has an observable behavior in a
given finite (but could be huge) set "Bad". We introduce a novel approach to
solve the problem that does not require integration testing. Instead, in our
approach, the global testing problem is reduced to testing individual
black-boxes in the system one by one in some given order. Using an
automata-theoretic approach, test sequences for each individual black-box are
generated from the system's description as well as the test results of
black-boxes prior to this black-box in the given order. In contrast to the
conventional compositional/modular verification/testing approaches, our
approach is essentially decompositional.
  Also, our technique is complete, sound, and can be carried out automatically.
Our experiment results show that the total number of tests needed to solve the
global testing problem is substantially small even for an extremely large
"Bad".
