  Testing on reactive systems is a well-known laborious activity on software
development due to their asynchronous interaction with the environment. In this
setting model based testing has been employed when checking conformance and
generating test suites of such systems using labeled transition system as a
formalism as well as the classical ioco conformance relation. In this work we
turn to a more complex scenario where the target systems have an auxiliary
memory, a stack. We then studied a more powerful model, the Visibly Pushdown
Labeled Transition System (VPTS), its variant Input/Output VPTS (IOVPTS), its
associated model Visibly Pushdown Automaton (VPA), and aspects of conformance
testing and test suite generation. This scenario is much more challenge since
the base model has a pushdown stack to capture more complex behaviors which
commonly found on reactive systems. We then defined a more general conformance
relation for pushdown reactive systems such that it prevents any observable
implementation behavior that was not already present in the given
specification. Further we gave an efficient algorithm to check conformance in
this testing scenario and also showed that it runs in worst case asymptotic
polynomial time in the size of both the given specification and the
implementation that are put under test.
