ansible/test/integration/targets/lookup_inventory_hostnames/main.yml

---
- hosts: localhost
  gather_facts: no
  tasks:
  - set_fact:
      hosts_a: "{{ lookup('inventory_hostnames', 'group01', wantlist=true) }}"
      hosts_b: "{{ groups['group01'] }}"
      exclude: "{{ lookup('inventory_hostnames', 'group01:!test03', wantlist=true) }}"
      intersect: "{{ lookup('inventory_hostnames', 'group01:&group02', wantlist=true) }}"
      nogroup: "{{ lookup('inventory_hostnames', 'nogroup01', wantlist=true) }}"
      doesnotexist: "{{ lookup('inventory_hostnames', 'doesnotexist', wantlist=true) }}"
      all: "{{ lookup('inventory_hostnames', 'all', wantlist=true) }}"

  - assert:
      that:
        - hosts_a == hosts_b
        - "'test03' not in exclude"
        - intersect == ['test03', 'test04']
        - nogroup == ['nogroup01']
        - doesnotexist == []
        - all|length == 12