1. A method, in a data processing system, for adjusting input values of testcases in the presence of dead-end constraints, comprising: analyzing a netlist, 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 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 to determine if a value associated with the constraint of the netlist results in a dead-end constraint condition; and adjusting an input to the netlist if the value associated with the constraint of the netlist results in a dead-end constraint condition.