healthcheck for etherpad sql

docker-compose.test.yml

@@ -29,6 +29,10 @@ services:
       MYSQL_COLLATION: utf8_general_ci
       MYSQL_CHARSET: utf8
       MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
+      timeout: 20s
+      retries: 20
     volumes:
       #- ep-mysql-volume:/var/lib/mysql
       - /srv/initdb/etherpad:/docker-entrypoint-initdb.d/
@@ -47,7 +51,7 @@ services:
       REQUIRE_SESSION: "true"   
     depends_on:
       etherpadsql:
-        condition: "service_started"
+        condition: "service_healthy"
     volumes:
       - /srv/APIKEY.txt:/opt/etherpad-lite/APIKEY.txt
 #     - ./deployment/mysql.cnf:/etc/mysql/conf.d