VHDL textio read file debug

Question

I am having some trouble debugging this program. I was given an assignment to read test vectors from a text file to test a program. The program and test bench code is written below. I cannot figure out why my simulation is coming up blank. No errors, the simulation window comes up, but it is blank. Any idea what the problem may be?

Module:

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity PAR is
Port ( data : in  STD_LOGIC_VECTOR (3 downto 0);
       parity : out  STD_LOGIC);
end PAR;

architecture Behavioral of PAR is
begin
proc: process
variable count: bit;
begin
for i in data'range loop
    if data(i)='1' then
        count:=not count;
    end if;
end loop;
if count='0' then
    parity<='0';
else 
    parity<='1';
end if;
wait;
end process;


end Behavioral;

Test Bench:

LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
USE std.textio.all;
use ieee.std_logic_textio.all;

ENTITY PAR_test IS
END PAR_test;

ARCHITECTURE behavior OF PAR_test IS 

    -- Component Declaration for the Unit Under Test (UUT)

    COMPONENT PAR
    PORT(
         data : IN  std_logic_vector(3 downto 0);
         parity : OUT  std_logic
        );
    END COMPONENT;


   --Inputs
   signal data : std_logic_vector(3 downto 0) := (others => '0');

    --Outputs
   signal parity : std_logic;
   -- No clocks detected in port list. Replace <clock> below with 
   -- appropriate port name 

BEGIN

    -- Instantiate the Unit Under Test (UUT)
   uut: PAR PORT MAP (
          data => data,
          parity => parity
        );

   TB: process
        file vec_file: text;
        variable buf_in: line;
        variable testv: std_logic_vector(0 to 4);
        begin
            file_open(vec_file,"PAR_file.txt,", read_mode);
        while not endfile (vec_file) loop
            readline (vec_file, buf_in);
            read(buf_in,testv);
            data(3) <= testv(0);
            data(2) <= testv(1);
            data(1) <= testv(2);
            data(0) <= testv(3);
            wait for 10 ns;
            assert (parity=testv(4))
                report "Test Failed" severity error;
        end loop;
    wait;
    END process;
    end;

Answer 1

in your "file_open.." line you have a "," that's not needed

wrong is:

file_open(vec_file,"PAR_file.txt,", read_mode);

correct is:

file_open(vec_file,"PAR_file.txt", read_mode);