4. derive input space partitioning test inputs for the genericstack class assuming the following method signatures: public genericstack (); public void push (object x); public object pop (); public boolean isempty (); assume the usual semantics for the genericstack. try to keep your partitioning simple and choose a small number of partitions and blocks. (a) list all of the input variables, including the state variables. (b) define characteristics of the input variables. make sure you cover all input variables. (c) define characteristics of inputs. (d) partition the characteristics into blocks. (e) define values for each block