[modbus_controller] Rename custom_command to custom_pdu; reject address 0; retire skip_updates (#18652)

tests/component_tests/modbus_controller/test_custom_pdu.py

@@ -0,0 +1,47 @@
+"""Schema-level config validation for custom_pdu and the deprecated custom_command alias.
+
+custom_command took a raw frame with a leading device address byte; custom_pdu takes the PDU only.
+The old key is still accepted at the schema level and auto-migrated later in final validate (which a
+bare-schema test can't reach), so these tests only cover what the schema itself enforces: the two keys
+are mutually exclusive, and custom_pdu takes byte-sized values.
+"""
+
+import pytest
+from voluptuous import Invalid, MultipleInvalid
+
+from esphome.components.modbus_controller import ModbusItemBaseSchema
+from esphome.components.modbus_controller.const import (
+    CONF_CUSTOM_COMMAND,
+    CONF_CUSTOM_PDU,
+)
+
+
+def test_custom_command_accepted_at_schema_level() -> None:
+    """custom_command validates at the schema level; migration/rejection happens in final validate."""
+    config = ModbusItemBaseSchema(
+        {CONF_CUSTOM_COMMAND: [0x01, 0x03, 0x00, 0x2A, 0x00, 0x01]}
+    )
+    assert config[CONF_CUSTOM_COMMAND] == [0x01, 0x03, 0x00, 0x2A, 0x00, 0x01]
+
+
+def test_custom_pdu_and_custom_command_mutually_exclusive() -> None:
+    """Only one custom source may be given; supplying both is a schema error."""
+    with pytest.raises((Invalid, MultipleInvalid)):
+        ModbusItemBaseSchema(
+            {
+                CONF_CUSTOM_PDU: [0x03, 0x00, 0x2A, 0x00, 0x01],
+                CONF_CUSTOM_COMMAND: [0x01, 0x03, 0x00, 0x2A, 0x00, 0x01],
+            }
+        )
+
+
+def test_custom_pdu_accepted() -> None:
+    """The new key takes PDU bytes (function code + data, no address byte)."""
+    config = ModbusItemBaseSchema({CONF_CUSTOM_PDU: [0x03, 0x00, 0x2A, 0x00, 0x01]})
+    assert config[CONF_CUSTOM_PDU] == [0x03, 0x00, 0x2A, 0x00, 0x01]
+
+
+def test_custom_pdu_rejects_non_byte_values() -> None:
+    """PDU entries are bytes; a word-sized value is a sign the old raw format is being used."""
+    with pytest.raises((Invalid, MultipleInvalid)):
+        ModbusItemBaseSchema({CONF_CUSTOM_PDU: [0x0103, 0x002A]})