Hi @mutmut,
I found the tutorial and followed it: Tutoriel: Lancer une image Docker de test
I followed the tutorial and installed the test image by doing this:
sudo docker run -d \
--log-driver json-file \
--log-opt max-size=10m \
--cgroupns=host \
--restart=always \
--privileged \
--network=host \
--name gladys-zigbee2mqtt-tuya-me201wz-test \
-e NODE_ENV=production \
-e SERVER_PORT=8001 \
-e TZ=Europe/Paris \
-e SQLITE_FILE_PATH=/var/lib/gladysassistant/gladys-production.db \
-v /var/run/docker.sock:/var/run/docker.sock \
-v /var/lib/gladys-zigbee2mqtt-tuya-me201wz-test:/var/lib/gladysassistant \
-v /dev:/dev \
-v /run/udev:/run/udev:ro \
gladysassistant/gladys:zigbee2mqtt-tuya-me201wz
I made sure to change the port and the storage space.
The instance is accessible on port 8001, no problem. But where I started having issues was with the MQTT broker and Zigbee2MQTT that I wanted to connect to the test instance. I thought that both Gladys instances could be connected to these containers but when I enable it on one it disconnects the other, it seems..
So for now I’ve stopped the test instance to avoid risking my production 
Here are my containers:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
caffb1ddd7e6 koenkk/zigbee2mqtt:1.42.0 "docker-entrypoint.s…" 43 minutes ago Up 43 minutes gladys-z2m-zigbee2mqtt
e2b29c057af6 eclipse-mosquitto:2.0.15 "/docker-entrypoint.…" 44 minutes ago Up 43 minutes gladys-z2m-mqtt
f869709d2ec6 eclipse-mosquitto:2.0.15 "/docker-entrypoint.…" About an hour ago Up 48 minutes eclipse-mosquitto
55728634212e gladysassistant/gladys:zigbee2mqtt-tuya-me201wz "docker-entrypoint.s…" About an hour ago Exited (0) 45 minutes ago gladys-zigbee2mqtt-tuya-me201wz-test
22290cf834c4 nodered/node-red:3.1 "./entrypoint.sh" 2 weeks ago Up 2 weeks (healthy) 0.0.0.0:1881-\u003e1880/tcp, [::]:1881-\u003e1880/tcp gladys-node-red
a5e4134c21d6 gladysassistant/gladys:v4 "docker-entrypoint.s…" 2 weeks ago Up 2 weeks gladys
942fa3b70db8 containrrr/watchtower "/watchtower --clean…" 3 weeks ago Up 3 weeks (healthy) 8080/tcp watchtower
And one question in passing: I don’t understand the difference between gladys-z2m-mqtt and eclipse-mosquitto, it’s the same image but with two different names, if someone can enlighten me 
Thanks for your help