---
- name: Perform some tests
  hosts: all
  become: no
  gather_facts: no


  tasks:
  - name: Do a debug thing
    debug:
      msg: "Hello world!"


  - name: Run a command
    command:
      cmd: uptime
    register: r_cmd_1


  - name: Clear errors if any
    meta: clear_host_errors


  - name: Show command output
    debug:
      msg: "{{ r_cmd_1.stdout | default('plop plop plop') }}"


  - name: Show the env variable for callback plugins
    debug:
      msg: "{{ lookup('env', 'ANSIBLE_CALLBACKS_ENABLED') }}"


...