`timescale 1us/1us

module debounce_tb;

logic rst_i;
logic clk_i;
logic signal_i;
logic signal_o;

integer i = 0;

debounce #(.STABLE_PERIOD(5)) uut (
  .rst_i(rst_i),
  .clk_i(clk_i),
  .signal_i(signal_i),
  .signal_o(signal_o)
);

string filename;
initial begin
`ifdef DUMP_FILE_NAME
  filename=`DUMP_FILE_NAME;
`else
  filename="debounce.lxt2";
`endif
  $dumpfile(filename); $dumpvars();

  clk_i = 0;
  rst_i = 1'b1;
  signal_i = 1'b1;
  #1
  rst_i = 1'b0;
  #1
  rst_i = 1'b1;
end

always #10 clk_i = ~clk_i;

initial begin
  // initial key press
  @(negedge clk_i);
  signal_i = ~signal_i;
  assert (signal_o == 1'b1);
 
  repeat(2) @(negedge clk_i);
 
  signal_i = ~signal_i;
  assert (signal_o == 1'b1);

  // try bouncing

  repeat(2) @(negedge clk_i);

  for (i=0; i < 20; i = i + 1) begin
    @(negedge clk_i);
    signal_i = ~signal_i;
    assert (signal_o == 1'b1);
  end
  @(negedge clk_i);
  signal_i = ~signal_i;
  assert (signal_o == 1'b1);

  repeat(10) @(negedge clk_i);
  assert (signal_o == 1'b0);

  repeat(10) @(negedge clk_i);
  signal_i = ~signal_i;

  repeat(10) @(negedge clk_i);
  assert (signal_o == 1'b1);

  repeat(10) @(negedge clk_i);
  $finish();
end

endmodule