Please note you could just point your path to the directory but to have control over the playlist you want to either
1. follow @Bashatee Radio  method here https://forum.sourcefabric.org/discussion/16909/autodj-sweetest-seen-fake-or-real-for-a-good-deal-free-free-no-unexpected-autoplay

2.here is the one I used
for a new playlist each time
find /srv/backup/files/test -type f -iname "*.mp3" > /srv/backup/playout/playlist/autodj.m3u

so in your case it would be
find /srv/backup/files/test -type f -iname "*.mp3" > /srv/backup/playout/playlist/myplaylist.txt


there is a whole lot of write up about space in name file name.Overall I use pyrenamer to change all my file names with underscore  or "-" 

why I use this.
I found that if you use request dynamics and a playlist is remove liquidsoap go heywire

so I have a script which check if autodj.m3u exsist and if its missing it will temporarily create one .

Most people do not know that Liquidsoap can run a cron like script so here is my checker
# This will ensure that if someone delete the playlist a new one is created

def maintbuilt_playlist()
       
command = "php /srv/backup/automation/autodj_php/startlist.php  > /dev/null 2>&1"
#log(command)
log(label="rebuilding playlist.AutoDj playlist is missing",level=5,command)
system(command)      

end 
exec_at (freq=180.,pred=({00h00m-23h59m}),maintbuilt_playlist)     

This script checks my playlist every 3 minutes and if its missing it rebuild it.
That way should my playlist become empty a new one is created
The load on the machine is negligible
Good luck