Test derivation based on user defined faults deals with the generation of tests that check if some parts of a given specification are correctly implemented in a corresponding implementation. In this paper, we present a method for test derivation based on user defined faults for Extended FSM (EFSM) specifications. Given an EFSM specification ES and a set of selected transitions of ES, the method returns a test suite that is complete with respect to output and transfer faults at the selected transitions, i.e., checks whether the selected transitions are correctly implemented in a corresponding EFSM implementation. Test derivation is based on a formally defined fault model (conformance relation and types of faults) and is guided by some conditions established for complete test derivation. To reduce test derivation efforts, we propose to use appropriate slices of the specification EFSM. The slices, on one hand, preserve the facilities of the original specification (before slicing) EFSM for traversing the selected transitions and for distinguishing their final states and on the other hand, these slices are much smaller than the given specification. Application examples and a simple case study are provided.