- name: Set variables to verify lookup_list
  set_fact: "{{ item if item is string else item[0] }}={{ item }}"
  with_list:
    - a
    - [b, c]
    - d

- name: Verify lookup_list
  assert:
    that:
        - a is defined
        - b is defined
        - c is not defined
        - d is defined
        - b is iterable and b is not string
        - b|length == 2
        - a == a
        - b == ['b', 'c']
        - d == d