esphome/tests/components/output/common.yaml

esphome:
  on_boot:
    then:
      - output.turn_off: light_output_1
      - output.turn_on: light_output_1
      - output.set_level:
          id: light_output_1
          level: 50%

output:
  - platform: ${output_platform}
    id: light_output_1
    pin: ${pin}