- name: create unindexed list
  shell: for i in $(seq 1 5); do echo "x" ; done;
  register: list_data

- name: create indexed list
  set_fact: "{{ item[1] + item[0]|string }}=set"
  with_indexed_items: "{{list_data.stdout_lines}}"

- name: verify with_indexed_items result
  assert:
    that:
        - "x0 == 'set'"
        - "x1 == 'set'"
        - "x2 == 'set'"
        - "x3 == 'set'"
        - "x4 == 'set'"

- block:
    - name: "EXPECTED FAILURE - test not a list"
      debug:
        msg: "{{ item.0 }} is {{ item.1 }}"
      with_indexed_items:
        "a": 1

    - fail:
        msg: "should not get here"

  rescue:
    - assert:
        that:
          - ansible_failed_task.name == "EXPECTED FAILURE - test not a list"
          - ansible_failed_result.msg == "with_indexed_items expects a list"