// timescale is <time unit> / <time precision>
`timescale 1 ns / 1 ns
module extender_tb();

  parameter M = 4, N = 8;
  logic [M-1:0] in;
  logic [N-1:0] out;
  logic sign;
  
  extender #(M, N) dut (.*);
  
  int i;
  initial begin
    for (i = 0; i < 2**2; i++) begin
      sign = i[0];  in = {i[1], {(M-1){1'b0}}}; #10;
      $display("t = %0t, %b %s %b", $time, in, sign ? "-+->" : "-0->", out);

    end  // for
    $stop;
  end  // initial
  
endmodule  // extender_tb