[pzem6l24] Add PZEM-6L24 three-phase energy monitor sensor (#17849)

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Co-authored-by: J. Nick Koston <nick@home-assistant.io>

tests/component_tests/pzem6l24/test_address.py

@@ -0,0 +1,28 @@
+"""The PZEM-6L24 answers unit addresses 1 to 247 only."""
+
+import pytest
+
+from esphome import config_validation as cv
+from esphome.components import modbus
+from esphome.components.pzem6l24.sensor import CONFIG_SCHEMA
+from esphome.const import CONF_ADDRESS
+from esphome.types import ConfigType
+
+
+def _sensor(**extra: object) -> ConfigType:
+    return CONFIG_SCHEMA({modbus.CONF_MODBUS_ID: "bus", **extra})
+
+
+def test_address_defaults_to_one() -> None:
+    assert _sensor()[CONF_ADDRESS] == 1
+
+
+@pytest.mark.parametrize("address", [1, 247])
+def test_address_in_unit_range_accepted(address: int) -> None:
+    assert _sensor(**{CONF_ADDRESS: address})[CONF_ADDRESS] == address
+
+
+@pytest.mark.parametrize("address", [0, 248, 255])
+def test_address_outside_unit_range_rejected(address: int) -> None:
+    with pytest.raises(cv.Invalid):
+        _sensor(**{CONF_ADDRESS: address})