ansible/test/integration/targets/handlers/test_listening_handlers.yml

---
- name: verify listening handlers
  hosts: A
  gather_facts: False
  connection: local
  tasks:
    - name: notify some handlers
      command: echo foo
      notify:
        - notify_listen
  post_tasks:
    - name: assert all defined handlers ran without error
      assert:
        that:
        - "notify_listen_ran_1 is defined"
        - "notify_listen_ran_2 is defined"
  handlers:
    - name: first listening handler has a name
      set_fact:
        notify_listen_ran_1: True
      listen: notify_listen
    # second listening handler does not
    - set_fact:
        notify_listen_ran_2: True
      listen: notify_listen