Testbench input 10500 Syntax Error

Question

I tried to create a simple hello world testbench for a two input AND gate in Quartus. I am consistently running into the following error:

Error (10500): VHDL syntax error at Scott_2InputAndGate_Test.vhd(19) near text "IN"; expecting an identifier ("in" is a reserved keyword), or a string literal

My code:

--------------------------------------
------------TOP LEVEL ENTITY----------
--------------------------------------
LIBRARY IEEE;
USE IEEE.std_logic_1164.all;
USE IEEE.numeric_std.all;


ENTITY s_2InputAndGate IS
    PORT(a, b : IN  std_logic;
            z : OUT std_logic);
END ENTITY s_2InputAndGate;


ARCHITECTURE behaviour OF s_2InputAndGate IS
    BEGIN
        z <= a AND b;

END ARCHITECTURE behaviour;


--------------------------------------
------------TESTBENCH-----------------
--------------------------------------
LIBRARY IEEE;
USE IEEE.std_logic_1164.all;
USE IEEE.numeric_std.all;

--No Entity for TestBench;
ENTITY s_2InputAndGate_Test IS END;



--Line 10
--Line 11
--Line 12...etc



--Behaviour of the Test bench;
ARCHITECTURE behaviour OF s_2InputAndGate_Test IS

    SIGNAL A_test, B_test : IN  std_logic;   --lINE(19 - ERROR HERE!)
                    Z_test: OUT std_logic;

    BEGIN
        A_test <= 0;
        B_test <= 0;

        WAIT FOR 50ns;

        A_test <= 0;
        B_test <= 1;

    WAIT FOR 50ns;

        A_test <= 1;
        B_test <= 0;

        WAIT FOR 50ns;

        A_test <= 1;
        B_test <= 1;

        WAIT;
END ARCHITECTURE behaviour;

The compiler seems to keep complaining about the signal declaration in the testbench. I have checked the syntax and can't seem to find any obvious problem with it. Anyone have any ideas why this line should prevent a successful compilation?

Answer 1

SIGNAL A_test, B_test : IN  std_logic;

Signals do not have a direction. Just use:

SIGNAL A_test, B_test : std_logic;

Also, your line Z_test: OUT std_logic; is not valid. You can add this signal declaration in with the other two once you remove the direction.