python: communication with console program

Question

I have console program(.exe) which is basically infinite loop:

1. accepts string input in special format(containing line breaks)
2. print string output in special format(containing line breaks)

To be specific, console program code looks like this:

1) read integers n, m

2) n times do:

 1. reak integer k
 2. read k integers

3) m times do:

 1. read integer k
 2. read k integers

4)do whatever

5)cout n x m characters which are in ('?', '.', 'X')

6) go to (1)

Here's what it looks like when I run it by hand:

I want to make python program interact with it, but it doesn't work and makes really wierd things.

Here's what I try to even make 1 input and take 1 output.

import subprocess

process = subprocess.Popen("Program.exe", encoding='utf-8', stdin=subprocess.PIPE)
with open('test.txt', 'r') as file:
    test = file.read()
test = test + '\n'
print(solver.communicate(input=test))
solver.kill()

Here's the result (output is normal until it start that weird infinite loop):

size:

20 rows. First quantity, then quantity of numbers:

20 columns. First quantity, then quantity of numbers:
.....XXXXX..........
.......XXXX.........
...XXX...XXX........
.XXXXXXX..XX........
.XXXXXXXX.XX........
XX.....XXX.XXXXX....
........XXXXXXXXXX..
....XXXXXXXXX.XXXXX.
...XXXXXXXXXXX..XXX.
..XXX...XXX.XXX..XXX
..XX...XXXXX.XXX..XX
..XX...XX..XXXXX..X.
...X..XX...XX.XXX...
......XX..XXX.XXX...
.....XXX..XX...XX...
.....XX..XX...XX....
.....XX.......X.....
....XXX.............
....XXX.............
....XXX.............

size: 
20 rows. First quantity, then quantity of numbers:

20 columns. First quantity, then quantity of numbers:
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????
????????????????????

size: 
20 rows. First quantity, then quantity of numbers:

20 columns. First quantity, then quantity of numbers:
????????????????????
.
and it repeats infinitely
.

The question marks mean that there's some input and it takes 20 20 from wherever, but I don't understand where it comes from.

What I want is reliable way to send console program a string and read one back.

Answer 1

I removed hint outputs in console program and it became as easy as just not using communicate. Here's what worked out:

import subprocess

process = subprocess.Popen("Program.exe", encoding='utf-8', stdin=subprocess.PIPE, stdout=subprocess.PIPE)
with open('test.txt', 'r') as file:
    test = file.read()
test = test + '\n'
process.stdin.write(test)
process.stdin.flush()
ans = ""
for line in process.stdout:
    ans = ans + process.stdout.readline()
print(ans)
solver.kill()