how to test without email / smtp ?

[moolight-seashell]

i have this issue when running with penpot-compose :

WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance.
10:12:30.877 [vert.x-eventloop-thread-0] ERROR com.qux.util.Config - mergeUser() > QUX_USER_ALLOW_SIGNUP > false
10:12:30.939 [vert.x-eventloop-thread-0] ERROR com.qux.MATC - createMail() > DISABLE MAIL SSL!
May 10, 2026 10:12:30 AM io.vertx.core.Starter
SEVERE: Failed in deploying verticle
java.lang.NullPointerException: Cannot invoke "Object.hashCode()" because "<parameter1>" is null
        at java.base/java.util.concurrent.ConcurrentHashMap.get(Unknown Source)
        at io.vertx.core.shareddata.impl.LocalMapImpl.get(LocalMapImpl.java:42)
        at io.vertx.ext.mail.impl.MailClientImpl.lookupHolder(MailClientImpl.java:173)
        at io.vertx.ext.mail.impl.MailClientImpl.<init>(MailClientImpl.java:53)
        at io.vertx.ext.mail.MailClient.createShared(MailClient.java:72)
        at com.qux.MATC.createMail(MATC.java:256)
        at com.qux.MATC.initMail(MATC.java:212)
        at com.qux.MATC.start(MATC.java:79)
        at io.vertx.core.AbstractVerticle.start(AbstractVerticle.java:108)
        at io.vertx.core.Verticle.start(Verticle.java:66)
        at io.vertx.core.impl.DeploymentManager.lambda$doDeploy$9(DeploymentManager.java:552)
        at io.vertx.core.impl.ContextImpl.executeTask(ContextImpl.java:366)
        at io.vertx.core.impl.EventLoopContext.lambda$executeAsync$0(EventLoopContext.java:38)
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:469)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:503)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Unknown Source)

and the default email settings

  qux-be:
    restart: always
    container_name: quant-ux-backend
    image: docker.io/klausenschaefersinho/quant-ux-backend
    volumes:
      - ./data/quant-ux-data:/app-data
    environment:
      - QUX_HTTP_HOST=http://quant-ux-frontend:8082
      - QUX_HTTP_PORT=8080
      - QUX_MONGO_DB_NAME=quantux
      - QUX_MONGO_TABLE_PREFIX=quantux
      - QUX_MONGO_CONNECTION_STRING=mongodb://quant-ux-mongo:27017
      - QUX_MAIL_USER=mail_admin@example.com
      - QUX_MAIL_PASSWORD=sTr0ngPa55w0Rd
      - QUX_MAIL_HOST=mail.example.com
      - QUX_JWT_PASSWORD=some-long-string-of-mix-case-chars-and-nums
      - QUX_IMAGE_FOLDER_USER=/app-data/qux-images
      - QUX_IMAGE_FOLDER_APPS=/app-data/qux-image-apps
      - TZ=America/Chicago
      - QUX_AUTH_SERVICE=qux
      - QUX_KEYCLOAK_SERVER=
      - QUX_KEYCLOAK_REALM=
      - QUX_USER_ALLOW_SIGNUP=false
      - QUX_USER_ALLOWED_DOMAINS=*
    depends_on:
      - mongo