ansible/test/integration/targets/hostname/tasks/test_normal.yml

- name: Run hostname module for real now
  hostname:
    name: crocodile.ansible.test.doesthiswork.net.example.com
  register: hn2

- name: Get hostname
  command: hostname
  register: current_after_hn2

- name: Run hostname again to ensure it does not change
  hostname:
    name: crocodile.ansible.test.doesthiswork.net.example.com
  register: hn3

- name: Get hostname
  command: hostname
  register: current_after_hn3

- assert:
    that:
      - hn2 is changed
      - hn3 is not changed
      - current_after_hn2.stdout == 'crocodile.ansible.test.doesthiswork.net.example.com'
      - current_after_hn2.stdout == current_after_hn2.stdout