[bluetooth_proxy] Scanner-state sync in set_mode; platform-gate tests (#18100)

tests/component_tests/bluetooth_proxy/test_outer_schema_mirror.py

@@ -2,9 +2,10 @@
 them without importing the esp32 BLE stack; pin the two declarations together.
 
 The outer schema carries no defaults (the per-platform schema applies them), so
-drift cannot surface in validation output — a key renamed or re-bounded in
+drift cannot surface in validation output — a key renamed or removed in
 _esp32_config_schema() but not here would silently vanish from the dashboard's
-field extractor. This test is what catches that.
+field extractor. This test is what catches that; validator bounds are pinned
+separately only for connection_slots (test_idf_max_connections_mirror).
 """
 
 import voluptuous as vol

tests/component_tests/bluetooth_proxy/test_platform_gates.py

@@ -0,0 +1,48 @@
+"""The three platform-gate branches: BLE-less platforms are rejected with the
+real reason, hub platforms reject GATT-only options by name, and the
+advertisement-only arm applies its own defaults."""
+
+import pytest
+
+from esphome import config_validation as cv
+from esphome.components import bluetooth_proxy
+from esphome.const import CONF_ACTIVE, KEY_TARGET_PLATFORM
+from esphome.core import CORE, KEY_CORE
+
+
+def _set_platform(platform: str) -> None:
+    CORE.data.setdefault(KEY_CORE, {})[KEY_TARGET_PLATFORM] = platform
+
+
+def test_ble_less_platform_gets_the_real_reason() -> None:
+    _set_platform("esp8266")
+    with pytest.raises(cv.Invalid, match="not supported on esp8266"):
+        bluetooth_proxy.CONFIG_SCHEMA({})
+
+
+def test_ble_less_platform_connection_keys_fall_through() -> None:
+    # The key-level rejection must not fire here — it would imply an
+    # advertisement-only proxy exists on this platform.
+    _set_platform("esp8266")
+    with pytest.raises(cv.Invalid, match="not supported on esp8266"):
+        bluetooth_proxy.CONFIG_SCHEMA({"connection_slots": 2})
+
+
+def test_hub_platform_rejects_active() -> None:
+    _set_platform("ln882x")
+    with pytest.raises(cv.Invalid, match="Active connections are not supported"):
+        bluetooth_proxy.CONFIG_SCHEMA({"active": True})
+
+
+def test_hub_platform_rejects_connection_keys_by_name() -> None:
+    _set_platform("ln882x")
+    with pytest.raises(cv.Invalid, match="'connection_slots' requires active"):
+        bluetooth_proxy.CONFIG_SCHEMA({"connection_slots": 2})
+    with pytest.raises(cv.Invalid, match="'cache_services' requires active"):
+        bluetooth_proxy.CONFIG_SCHEMA({"cache_services": True})
+
+
+def test_hub_platform_accepts_the_advertisement_only_shape() -> None:
+    _set_platform("ln882x")
+    validated = bluetooth_proxy.CONFIG_SCHEMA({})
+    assert validated[CONF_ACTIVE] is False