Growing acceptance of model-based test generation in the industry has created a need for a tester-friendly model construction process and associated tools. In this paper, we present an automated approach for checking consistency and completeness of testing models for interactive systems. The testing models are described in terms of operations provided by the system under test (SUT). Each operation is specified as a set of possible results each with a guard condition and a set of actions on its parameters and the system state. The consistency and completeness checks performed include identification of malformed models, irrelevant state variables, incomplete and redundant guard conditions, missing data values, and nondeterminism in and executability of operation results. We review our testing requirements model, and describe various consistency checks performed on this model. We illustrate these checks with an example test model, and also present algorithms used to perform our analysis.