In this paper we describe faults that can occur in reversible circuits. In particular, we focus on comparison of faults that can appear in classical circuits with faults that can occur in quantum technology. The analysis is generalized from the point of view of technologies such as information reversible and energy reversible. We show that contrary to classical non-reversible transistor based circuits, it is necessary to specify what type of reversible circuit we are describing. Moreover the level of faults and their analysis must be revised to precisely capture the effects and properties of quantum gates and quantum circuits. By not doing so the available testing approaches adapted from classical circuits could not be able to properly developed to relevant faults. In addition, if the classical faults are directly applied without revision and modifications, the presented testing procedure would be testing for such faults that cannot physically occur in the given implementation of reversible circuits.