simple change using --check

gistfile1.txt

(ansible)[network]$ ansible-playbook change_hostname.yaml --check

PLAY [veos01] ******************************************************************

TASK [eos_config] **************************************************************
changed: [veos01]

TASK [debug] *******************************************************************
ok: [veos01] => {
    "result": {
        "changed": true,
        "updates": [
            "hostname foo"
        ]
    }
}

PLAY RECAP *********************************************************************
veos01                     : ok=2    changed=1    unreachable=0    failed=0

(ansible)[network]$
(ansible)[network]$
(ansible)[network]$
(ansible)[network]$ cat change_hostname.yaml
---
- hosts: veos01
  gather_facts: no
  connection: local

  tasks:
    - eos_config:
        lines:
          - hostname foo
        provider: "{{ cli }}"
      register: result
    - debug: var=result


(ansible)[network]$ ansible-playbook change_hostname.yaml

PLAY [veos01] ******************************************************************

TASK [eos_config] **************************************************************
changed: [veos01]

TASK [debug] *******************************************************************
ok: [veos01] => {
    "result": {
        "changed": true,
        "responses": [
            ""
        ],
        "updates": [
            "hostname foo"
        ]
    }
}

PLAY RECAP *********************************************************************
veos01                     : ok=2    changed=1    unreachable=0    failed=0






(ansible)[network]$ ansible-playbook change_hostname.yaml

PLAY [veos01] ******************************************************************

TASK [eos_config] **************************************************************
ok: [veos01]

TASK [debug] *******************************************************************
ok: [veos01] => {
    "result": {
        "changed": false,
        "updates": []
    }
}

PLAY RECAP *********************************************************************
veos01                     : ok=2    changed=0    unreachable=0    failed=0