test: enable mosquitto password auth; add mqttping endpoint; use credentials in subscriber; publish defaults

test/docker-compose.yml

@@ -14,6 +14,8 @@ services:
       - MQTT_BROKER=tcp://mosquitto:1883
       - MQTT_CLIENT_ID=lambdaiot-server
       - MQTT_TOPIC=lambdaiot
+      - MQTT_USERNAME=testuser
+      - MQTT_PASSWORD=testpass
     depends_on:
       - mosquitto
     # server image now waits for MQTT broker itself via entrypoint
@@ -27,6 +29,8 @@ services:
       - mosquitto_data:/mosquitto/data
       - mosquitto_log:/mosquitto/log
       - ./mosquitto.conf:/mosquitto/config/mosquitto.conf:ro
+    # ensure a password file exists and start mosquitto with our config
+    command: sh -c "mosquitto_passwd -b /mosquitto/config/passwordfile testuser testpass >/dev/null 2>&1 || true; /usr/sbin/mosquitto -c /mosquitto/config/mosquitto.conf"
     healthcheck:
       test: ["CMD", "sh", "-c", "nc -z localhost 1883 || exit 1"]
       interval: 2s
@@ -41,6 +45,8 @@ services:
     environment:
       - MQTT_BROKER=mosquitto:1883
       - MQTT_TOPIC=lambdaiot
+      - MQTT_USERNAME=testuser
+      - MQTT_PASSWORD=testpass
     command: sh -c "pip install paho-mqtt && python subscribe.py"
     depends_on:
       - mosquitto