module psychic_tester_tb ();
  logic       clk, rst, submit_ext, psychic;
  logic [3:0] guess_ext;

  // instantiate device under test
  psychic_tester dut (.*);
  
  // generate simulated clock
  parameter T = 20;  // clock period
  initial
    clk = 0;
  always
    #(T/2)  clk <= ~clk;

  // initial block
  initial begin
  
	// test case 0: verify reset behavior
	{rst, submit_ext, guess_ext} <= 6'b1_0_0000;  @(posedge clk);// reset
   {rst, submit_ext, guess_ext} <= 6'b0_0_0000;  @(posedge clk);// reset
	
	// test case 1: user inputs guesses but did not trigger submit button
	// guess will not submit even if the guess matches the correct pattern
	{submit_ext, guess_ext} <= 5'b0_0000;         @(posedge clk);
	{submit_ext, guess_ext} <= 5'b0_0001;         @(posedge clk);
																 @(posedge clk);
	// test case 2: user guesses wrong in their 5th try
	// count_correct should be cleared and psychic signal should be false
	{submit_ext, guess_ext} <= 5'b0_0000;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (0)
	{submit_ext, guess_ext} <= 5'b0_0001;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (1)
	{submit_ext, guess_ext} <= 5'b0_0011;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (2)
	{submit_ext, guess_ext} <= 5'b0_0111;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (3)
	{submit_ext, guess_ext} <= 5'b0_1111;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// wrong guess
	                                              @(posedge clk);
	
	// test case 3: Reset and user guesses correctly 8 times
	// psychic signal should be triggered to true
	{rst, submit_ext, guess_ext} <= 6'b1_0_0000;  @(posedge clk);// reset
   {rst, submit_ext, guess_ext} <= 6'b0_0_0000;  @(posedge clk);// reset
	{submit_ext, guess_ext} <= 5'b0_0000;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (1)
	{submit_ext, guess_ext} <= 5'b0_0001;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (2)
	{submit_ext, guess_ext} <= 5'b0_0011;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (3)
	{submit_ext, guess_ext} <= 5'b0_0111;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (4)
	{submit_ext, guess_ext} <= 5'b0_1110;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (5)
	{submit_ext, guess_ext} <= 5'b0_1101;  		 @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (6)
	{submit_ext, guess_ext} <= 5'b0_1011;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (7)
	{submit_ext, guess_ext} <= 5'b0_0110;         @(posedge clk);
	submit_ext <= 1'b1;                           @(posedge clk);// correct (8)
	submit_ext <= 1'b0;                           @(posedge clk);
	                                              @(posedge clk);
																 @(posedge clk);
																 @(posedge clk);// psychic is HIGH

    $stop;
  end









endmodule  // psychic_tester_tb