ansible/test/integration/targets/handlers/80880.yml

---
- name: Test notification of handlers from other handlers
  hosts: localhost
  gather_facts: no
  handlers:
    - name: Handler 1
      debug:
        msg: Handler 1
      changed_when: true
      notify: Handler 2
      register: handler1_res
    - name: Handler 2
      debug:
        msg: Handler 2
      changed_when: true
      notify: Handler 3
      register: handler2_res
    - name: Handler 3
      debug:
        msg: Handler 3
      register: handler3_res
  tasks:
    - name: Trigger handlers
      ansible.builtin.debug:
        msg: Task 1
      changed_when: true
      notify: Handler 1
  post_tasks:
    - name: Assert results
      ansible.builtin.assert:
        that:
        - "handler1_res is defined and handler1_res is success"
        - "handler2_res is defined and handler2_res is success"
        - "handler3_res is defined and handler3_res is success"