| Fault modeling is one of the most challenging aspects of testing an implementation with timing related constraints. Two new models for test generation in timed systems are introduced in this thesis: one for timed extended finite state machines (EFSMs) and the other for extended timed automata (TA). Both of our models are designed for test generation purposes. They are more powerful in terms of their fault detection capabilities, simpler, more intuitive, and computationally less complex than their existing counterparts reported in the literature.;The fault masking phenomenon was first introduced in our earlier work, where single timing faults, although individually detectable, can mask each other's faulty behavior, making a faulty implementation under test (IUT) indistinguishable from a non-faulty one during testing. In this thesis, a formal definition is introduced to properly represent a fault masking phenomena for a class of timing faults. We formally prove that the timed EFSM model augmented by our algorithms for single timing faults are also capable of detecting multiple occurrences of pairwise combinations of these timing faults. After our augmentations are applied to the system models, the fault masking does not hold during testing because test sequences generated from the augmented models do not satisfy the necessary conditions of fault masking. Our graph augmentation algorithms for timed EFSM systems are applied only to the model, and not to the IUT itself or its specification.;In addition, we introduce new graph augmentation algorithms for TA models in this thesis. We show that the augmented TA models can be generated by applying a set of augmentation algorithms such that the resulting test automata has the capability to detect the simultaneous occurrences of a class of single timing faults during testing. We show that, the zone graph, representing a real time system defined as a TA model, has limited fault detection capability for certain timed traces. However, the timed trace obtained from our augmented zone graph, which is constructed from our test automata, can be used as a basis to generate test sequences for the original system for detecting simultaneous occurrences of such timing faults. |
