esphome/tests/components/datetime/common-triggers.yaml

datetime:
  - platform: template
    name: Datetime Trigger Test
    id: datetime_trigger_test
    type: datetime
    optimistic: true
    on_value:
      - logger.log:
          format: "New value %04d-%02d-%02d"
          args: [x.year, x.month, x.day_of_month]