$ cat tests_create_lv_size_equal_to_vg.yml
---
- hosts: all
  become: true
  vars:
    storage_safe_mode: false
    mount_location: '/opt/test1'
    volume_group_size: '10g'
    lv_size: '10g'
    unused_disk_subfact: '{{ ansible_devices[unused_disks[0]] }}'
    disk_size: '{{ unused_disk_subfact.sectors|int *
                   unused_disk_subfact.sectorsize|int }}'

  tasks:
    - include_role:
        name: linux-system-roles.storage

    - include_tasks: get_unused_disk.yml
      vars:
        min_size: "{{ volume_group_size }}"
        max_return: 1

    - name: Create one lv which size is equal to vg size
      include_role:
        name: linux-system-roles.storage
      vars:
          storage_pools:
            - name: foo
              disks: "{{ unused_disks }}"
              volumes:
                - name: test1
                  size: "{{ lv_size }}"
                  mount_point: "{{ mount_location }}"

    - include_tasks: verify-role-results.yml

    - name: Clean up
      include_role:
        name: linux-system-roles.storage
      vars:
          storage_pools:
            - name: foo
              disks: "{{ unused_disks }}"
              state: "absent"
              volumes:
                - name: test1
                  mount_point: "{{ mount_location }}"

    - include_tasks: verify-role-results.yml



output:
TASK [linux-system-roles.storage : debug] ********************************************
task path: /home/system-role/storage/tasks/main-blivet.yml:84
ok: [192.168.122.6] => {
    "_storage_pools": [
        {
            "disks": [
                "vdb"
            ],
            "encryption": false,
            "encryption_cipher": null,
            "encryption_key": null,
            "encryption_key_size": null,
            "encryption_luks_version": null,
            "encryption_password": null,
            "name": "foo",
            "raid_chunk_size": null,
            "raid_device_count": null,
            "raid_level": null,
            "raid_metadata_version": null,
            "raid_spare_count": null,
            "state": "present",
            "type": "lvm",
            "volumes": [
                {
                    "encryption": false,
                    "encryption_cipher": null,
                    "encryption_key": null,
                    "encryption_key_size": null,
                    "encryption_luks_version": null,
                    "encryption_password": null,
                    "fs_create_options": "",
                    "fs_label": "",
                    "fs_overwrite_existing": true,
                    "fs_type": "xfs",
                    "mount_check": 0,
                    "mount_device_identifier": "uuid",
                    "mount_options": "defaults",
                    "mount_passno": 0,
                    "mount_point": "/opt/test1",
                    "name": "test1",
                    "pool": "foo",
                    "raid_chunk_size": null,
                    "raid_device_count": null,
                    "raid_level": null,
                    "raid_metadata_version": null,
                    "raid_spare_count": null,
                    "size": "10g",
                    "state": "present",
                    "type": "lvm"
                }
            ]
        }
    ]
}

TASK [linux-system-roles.storage : debug] ********************************************
task path: /home/system-role/storage/tasks/main-blivet.yml:87
ok: [192.168.122.6] => {
    "_storage_volumes": []
}

TASK [linux-system-roles.storage : get required packages] ****************************
task path: /home/system-role/storage/tasks/main-blivet.yml:90
ok: [192.168.122.6] => {"actions": [], "changed": false, "crypts": [], "leaves": [], "mounts": [], "packages": ["lvm2", "xfsprogs"], "pools": [], "volumes": []}

TASK [linux-system-roles.storage : make sure required packages are installed] ********
task path: /home/system-role/storage/tasks/main-blivet.yml:99
ok: [192.168.122.6] => {"changed": false, "msg": "Nothing to do", "rc": 0, "results": []}

TASK [linux-system-roles.storage : manage the pools and volumes to match the specified state] ***
task path: /home/system-role/storage/tasks/main-blivet.yml:104
fatal: [192.168.122.6]: FAILED! => {"actions": [], "changed": false, "crypts": [], "leaves": [], "mounts": [], "msg": "specified size for volume '10 GiB' exceeds available space in pool 'foo' (10 GiB)", "packages": [], "pools": [], "volumes": []}

PLAY RECAP ***************************************************************************
192.168.122.6              : ok=35   changed=0    unreachable=0    failed=1    skipped=15   rescued=0    ignored=0

I wrote a new test case for this bz:
https://github.com/linux-system-roles/storage/pull/189

Upstream Pull Request: https://github.com/linux-system-roles/storage/pull/199

test pass with rhel-system-roles-1.0.0-28.el8

move to verified

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (rhel-system-roles bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2021:1909