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

- name: Test handlers are executed in the order they are defined, not notified
  hosts: localhost
  gather_facts: false
  tasks:
    - set_fact:
        foo: ''
      changed_when: true
      notify:
        - handler4
        - handler3
        - handler1
        - handler2
        - handler5
    - name: EXPECTED FAILURE
      fail:
      when: test_force_handlers | default(false) | bool
  handlers:
    - name: handler1
      set_fact:
        foo: "{{ foo ~ 1 }}"
    - name: handler2
      set_fact:
        foo: "{{ foo ~ 2 }}"
    - name: handler3
      set_fact:
        foo: "{{ foo ~ 3 }}"
    - name: handler4
      set_fact:
        foo: "{{ foo ~ 4 }}"
    - name: handler5
      assert:
        that:
          - foo == '1234'
        fail_msg: "{{ foo }}"