1. A method, in a data processing system, for adjusting input values of testcases in the presence of dead-end constraints, comprising: analyzing, by a processor of the data processing system, a netlist stored in a storage device associated with the data processing system, for a constraint of the netlist, to identify a time step parameter associated with the constraint for use in identifying dead-end constraint conditions; simulating, by the processor, the netlist for a predetermined number of time steps; evaluating, at each time step, a state of elements of the netlist for a period of time steps in the future of the simulation, based on the time step parameter; determining, by the processor, whether a value associated with the constraint of the netlist results in a dead-end constraint condition for one or more of the time steps in the future; and adjusting, by the processor, an input to the netlist in response to the value associated with the constraint of the netlist resulting in a dead-end constraint condition.