Program for testing https://www.codingame.com/ide/puzzle/shadows-of-the-knight-episode-1

tester.py

import subprocess
import random
ROOM_SIZE = 100
xb = random.randint(0, ROOM_SIZE)
yb = random.randint(0, ROOM_SIZE)

xs = random.randint(0, ROOM_SIZE)
ys = random.randint(0, ROOM_SIZE)

print("Open prog")
prog = subprocess.Popen(['python3', 'testable.py'], stdin=subprocess.PIPE, stdout=subprocess.PIPE, text=True)
steps = 0
print(ROOM_SIZE, ROOM_SIZE, file=prog.stdin)
print(999, file=prog.stdin)
print(xs, ys, file=prog.stdin)

steps = 99
while (xs, ys) != (xb, yb):
    steps -= 1
    if steps == 0:
        print("Loop!")
        print("True position: ", xb, yb)
        exit(1)

    print("Current position is", xs, ys)
    code = ''
    if ys < yb: code += 'D'
    if ys > yb: code += 'U'
    if xs < xb: code += 'R'
    if xs > xb: code += 'L'
    print("Dir: ", code)
    print(code, file=prog.stdin, flush=True)

    import sys
    sys.stdin = prog.stdout
    xs, ys = map(int, input().split())
print("Result OK")
print("Current position is", xs, ys)

print("True position: ", xb, yb)