ansible/test/integration/targets/ssh_agent/test_key.yml

- ssh_keygen:
    type: "{{ item }}"
    passphrase: passphrase
  register: sshkey

- slurp:
    path: ~/.ssh/authorized_keys
  register: akeys

- copy:
    content: |
      {{ sshkey.public_key }}
      {{ akeys.content|b64decode }}      
    dest: ~/.ssh/authorized_keys
    mode: '0400'

- block:
    - ping:

    - name: list keys from agent
      ssh_agent:
        action: list
      register: keys

    - assert:
        that:
          - keys.nkeys == ansible_loop.index
          - keys['keys'][ansible_loop.index0].fingerprint == fingerprint

    - name: key already exists in the agent
      ping:
  vars:
    ansible_password: ~
    ansible_ssh_password: ~
    ansible_ssh_private_key_file: ~
    ansible_ssh_private_key: '{{ sshkey.private_key }}'
    ansible_ssh_private_key_passphrase: passphrase
    fingerprint: '{{ sshkey.fingerprint }}'