How to unit test (HUnit) when you only allowed to submit the module name "Main"?

This is question for multiplayer and contests.

I want to test my code using HUnit by writing separate test file

-- code.hs to submit to codingame
module Game where

main = do

-- test.hs for local test
import Game
import Test.HUnit

tests = ...

main = do
    _ <- runTestTT tests

but when I change module name to anything other than Main the code won’t run on codingame

Standard Error Stream:
/usr/bin/stdbuf: failed to run command `/tmp/Answer': No such file or directory

I have to comment/uncomment the line

module Game where

every time when switching between test locally and run remotely

I don’t know how/if you can use multiple files. When debugging locally, I use something like:

int magic = -1;
int maxTime = 50;
#if DEBUG //set by my IDE, but not by CodinGame
magic = 20;
maxTime = 500000000;

you could do that as a workaround.

Using this small library shall allow you to do so, albeit with some minor constraints : But I do reckon it is not the best solution if you use the online IDE frequently.