Write a testbench to check that the module `passcode` follows the FSM discussed in class.
-- Testbench for 4-bit adder
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use std.textio.all;
entity adder_test is
-- No ports, since this is a testbench
end adder_test;
architecture test of adder_test is
component adder is
port(
a : in unsigned(3 downto 0);
b : in unsigned(3 downto 0);
sum : out unsigned(3 downto 0)
);
end component;
begin
end test;