esphome/tests/components/ota/common.yaml

wifi:
  ssid: MySSID
  password: password1

ota:
  - platform: esphome
    password: "superlongpasswordthatnoonewillknow"
    port: 3286
    on_begin:
      then:
        - logger.log: "OTA start"
    on_progress:
      then:
        - logger.log:
            format: "OTA progress %0.1f%%"
            args: ["x"]
    on_end:
      then:
        - logger.log: "OTA end"
    on_error:
      then:
        - logger.log:
            format: "OTA update error %d"
            args: ["x"]
    on_state_change:
      then:
        lambda: >-
          ESP_LOGD("ota", "State %d", state);