- block:
  - name: Disable ubuntu repos so system packages are not upgraded and do not change testing env
    command: mv /etc/apt/sources.list /etc/apt/sources.list.backup

  - name: install latest foo
    apt:
      name: foo
      state: latest
      allow_unauthenticated: yes

  - name: check foo version
    shell: dpkg -s foo | grep Version | awk '{print $2}'
    register: apt_downgrade_foo_version

  - name: ensure the correct version of foo has been installed
    assert:
      that:
        - "'1.0.1' in apt_downgrade_foo_version.stdout"

  - name: try to downgrade foo
    apt:
      name: foo=1.0.0
      state: present
      allow_unauthenticated: yes
    ignore_errors: yes
    register: apt_downgrade_foo_fail

  - name: verify failure of downgrading without allow downgrade flag
    assert:
      that:
        - apt_downgrade_foo_fail is failed

  - name: try to downgrade foo with flag
    apt:
      name: foo=1.0.0
      state: present
      allow_downgrade: yes
      allow_unauthenticated: yes
    register: apt_downgrade_foo_succeed

  - name: verify success of downgrading with allow downgrade flag
    assert:
      that:
        - apt_downgrade_foo_succeed is success

  - name: check foo version
    shell: dpkg -s foo | grep Version | awk '{print $2}'
    register: apt_downgrade_foo_version

  - name: check that version downgraded correctly
    assert:
      that:
        - "'1.0.0' in apt_downgrade_foo_version.stdout"
        - "{{ apt_downgrade_foo_version.changed }}"

  - name: downgrade foo with flag again
    apt:
      name: foo=1.0.0
      state: present
      allow_downgrade: yes
      allow_unauthenticated: yes
    register: apt_downgrade_second_downgrade

  - name: check that nothing has changed (idempotent)
    assert:
      that:
        - "apt_downgrade_second_downgrade.changed == false"

  always:
    - name: Clean up
      apt:
        pkg: foo,foobar
        state: absent
        autoclean: yes

    - name: Restore ubuntu repos
      command: mv /etc/apt/sources.list.backup /etc/apt/sources.list