Help with template sensor with nested json

Actually I can’t even get file sensor to work in home assistant.

YAML

homeassistant:
  whitelist_external_dirs:
    - /config/smartctl

sensor:
  - platform: file
    name: testone
    file_path: "/config/smartctl/test.json"
    value_template: '{{ value_json }}'
  - platform: file
    name: testtwo
    file_path: "/config/smartctl/test.json"
    value_template: "{{ value_json.test }}"

/config/smartctl/test.json

{
  "test": "hello world"
}

Proof that home assistant can read the test.json file

mike@server:~$ docker exec -it homeassistant bash
bash-5.0# cat /config/smartctl/test.json
{
  "test": "hello world"
}bash-5.0#

Unfortunately both the sensors are empty