feat: add Home Assistant integration (REST tools + WebSocket gateway)

- Add ha_list_entities, ha_get_state, ha_call_service tools via REST API
- Add WebSocket gateway adapter for real-time state_changed event monitoring
- Support domain/entity filtering, cooldown, and auto-reconnect with backoff
- Use REST API for outbound notifications to avoid WS race condition
- Gate tool availability on HASS_TOKEN env var
- Add 82 unit tests covering real logic (filtering, payload building, event pipeline)

tests/tools/test_homeassistant_tool.py

@@ -0,0 +1,281 @@
+"""Tests for the Home Assistant tool module.
+
+Tests real logic: entity filtering, payload building, response parsing,
+handler validation, and availability gating.
+"""
+
+import json
+
+import pytest
+
+from tools.homeassistant_tool import (
+    _check_ha_available,
+    _filter_and_summarize,
+    _build_service_payload,
+    _parse_service_response,
+    _get_headers,
+    _handle_get_state,
+    _handle_call_service,
+)
+
+
+# ---------------------------------------------------------------------------
+# Sample HA state data (matches real HA /api/states response shape)
+# ---------------------------------------------------------------------------
+
+SAMPLE_STATES = [
+    {"entity_id": "light.bedroom", "state": "on", "attributes": {"friendly_name": "Bedroom Light", "brightness": 200}},
+    {"entity_id": "light.kitchen", "state": "off", "attributes": {"friendly_name": "Kitchen Light"}},
+    {"entity_id": "switch.fan", "state": "on", "attributes": {"friendly_name": "Living Room Fan"}},
+    {"entity_id": "sensor.temperature", "state": "22.5", "attributes": {"friendly_name": "Kitchen Temperature", "unit_of_measurement": "C"}},
+    {"entity_id": "climate.thermostat", "state": "heat", "attributes": {"friendly_name": "Main Thermostat", "current_temperature": 21}},
+    {"entity_id": "binary_sensor.motion", "state": "off", "attributes": {"friendly_name": "Hallway Motion"}},
+    {"entity_id": "sensor.humidity", "state": "55", "attributes": {"friendly_name": "Bedroom Humidity", "area": "bedroom"}},
+]
+
+
+# ---------------------------------------------------------------------------
+# Entity filtering and summarization
+# ---------------------------------------------------------------------------
+
+
+class TestFilterAndSummarize:
+    def test_no_filters_returns_all(self):
+        result = _filter_and_summarize(SAMPLE_STATES)
+        assert result["count"] == 7
+        ids = {e["entity_id"] for e in result["entities"]}
+        assert "light.bedroom" in ids
+        assert "climate.thermostat" in ids
+
+    def test_domain_filter_lights(self):
+        result = _filter_and_summarize(SAMPLE_STATES, domain="light")
+        assert result["count"] == 2
+        for e in result["entities"]:
+            assert e["entity_id"].startswith("light.")
+
+    def test_domain_filter_sensor(self):
+        result = _filter_and_summarize(SAMPLE_STATES, domain="sensor")
+        assert result["count"] == 2
+        ids = {e["entity_id"] for e in result["entities"]}
+        assert ids == {"sensor.temperature", "sensor.humidity"}
+
+    def test_domain_filter_no_matches(self):
+        result = _filter_and_summarize(SAMPLE_STATES, domain="media_player")
+        assert result["count"] == 0
+        assert result["entities"] == []
+
+    def test_area_filter_by_friendly_name(self):
+        result = _filter_and_summarize(SAMPLE_STATES, area="kitchen")
+        assert result["count"] == 2
+        ids = {e["entity_id"] for e in result["entities"]}
+        assert "light.kitchen" in ids
+        assert "sensor.temperature" in ids
+
+    def test_area_filter_by_area_attribute(self):
+        result = _filter_and_summarize(SAMPLE_STATES, area="bedroom")
+        ids = {e["entity_id"] for e in result["entities"]}
+        # "Bedroom Light" matches via friendly_name, "Bedroom Humidity" matches via area attr
+        assert "light.bedroom" in ids
+        assert "sensor.humidity" in ids
+
+    def test_area_filter_case_insensitive(self):
+        result = _filter_and_summarize(SAMPLE_STATES, area="KITCHEN")
+        assert result["count"] == 2
+
+    def test_combined_domain_and_area(self):
+        result = _filter_and_summarize(SAMPLE_STATES, domain="sensor", area="kitchen")
+        assert result["count"] == 1
+        assert result["entities"][0]["entity_id"] == "sensor.temperature"
+
+    def test_summary_includes_friendly_name(self):
+        result = _filter_and_summarize(SAMPLE_STATES, domain="climate")
+        assert result["entities"][0]["friendly_name"] == "Main Thermostat"
+        assert result["entities"][0]["state"] == "heat"
+
+    def test_empty_states_list(self):
+        result = _filter_and_summarize([])
+        assert result["count"] == 0
+
+    def test_missing_attributes_handled(self):
+        states = [{"entity_id": "light.x", "state": "on"}]
+        result = _filter_and_summarize(states)
+        assert result["count"] == 1
+        assert result["entities"][0]["friendly_name"] == ""
+
+
+# ---------------------------------------------------------------------------
+# Service payload building
+# ---------------------------------------------------------------------------
+
+
+class TestBuildServicePayload:
+    def test_entity_id_only(self):
+        payload = _build_service_payload(entity_id="light.bedroom")
+        assert payload == {"entity_id": "light.bedroom"}
+
+    def test_data_only(self):
+        payload = _build_service_payload(data={"brightness": 255})
+        assert payload == {"brightness": 255}
+
+    def test_entity_id_and_data(self):
+        payload = _build_service_payload(
+            entity_id="light.bedroom",
+            data={"brightness": 200, "color_name": "blue"},
+        )
+        assert payload["entity_id"] == "light.bedroom"
+        assert payload["brightness"] == 200
+        assert payload["color_name"] == "blue"
+
+    def test_no_args_returns_empty(self):
+        payload = _build_service_payload()
+        assert payload == {}
+
+    def test_data_does_not_overwrite_entity_id(self):
+        payload = _build_service_payload(
+            entity_id="light.a",
+            data={"entity_id": "light.b"},
+        )
+        # data.update overwrites entity_id set earlier
+        assert payload["entity_id"] == "light.b"
+
+
+# ---------------------------------------------------------------------------
+# Service response parsing
+# ---------------------------------------------------------------------------
+
+
+class TestParseServiceResponse:
+    def test_list_response_extracts_entities(self):
+        ha_response = [
+            {"entity_id": "light.bedroom", "state": "on", "attributes": {}},
+            {"entity_id": "light.kitchen", "state": "on", "attributes": {}},
+        ]
+        result = _parse_service_response("light", "turn_on", ha_response)
+        assert result["success"] is True
+        assert result["service"] == "light.turn_on"
+        assert len(result["affected_entities"]) == 2
+        assert result["affected_entities"][0]["entity_id"] == "light.bedroom"
+
+    def test_empty_list_response(self):
+        result = _parse_service_response("scene", "turn_on", [])
+        assert result["success"] is True
+        assert result["affected_entities"] == []
+
+    def test_non_list_response(self):
+        # Some HA services return a dict instead of a list
+        result = _parse_service_response("script", "run", {"result": "ok"})
+        assert result["success"] is True
+        assert result["affected_entities"] == []
+
+    def test_none_response(self):
+        result = _parse_service_response("automation", "trigger", None)
+        assert result["success"] is True
+        assert result["affected_entities"] == []
+
+    def test_service_name_format(self):
+        result = _parse_service_response("climate", "set_temperature", [])
+        assert result["service"] == "climate.set_temperature"
+
+
+# ---------------------------------------------------------------------------
+# Handler validation (no mocks - these paths don't reach the network)
+# ---------------------------------------------------------------------------
+
+
+class TestHandlerValidation:
+    def test_get_state_missing_entity_id(self):
+        result = json.loads(_handle_get_state({}))
+        assert "error" in result
+        assert "entity_id" in result["error"]
+
+    def test_get_state_empty_entity_id(self):
+        result = json.loads(_handle_get_state({"entity_id": ""}))
+        assert "error" in result
+
+    def test_call_service_missing_domain(self):
+        result = json.loads(_handle_call_service({"service": "turn_on"}))
+        assert "error" in result
+        assert "domain" in result["error"]
+
+    def test_call_service_missing_service(self):
+        result = json.loads(_handle_call_service({"domain": "light"}))
+        assert "error" in result
+        assert "service" in result["error"]
+
+    def test_call_service_missing_both(self):
+        result = json.loads(_handle_call_service({}))
+        assert "error" in result
+
+    def test_call_service_empty_strings(self):
+        result = json.loads(_handle_call_service({"domain": "", "service": ""}))
+        assert "error" in result
+
+
+# ---------------------------------------------------------------------------
+# Availability check
+# ---------------------------------------------------------------------------
+
+
+class TestCheckAvailable:
+    def test_unavailable_without_token(self, monkeypatch):
+        monkeypatch.delenv("HASS_TOKEN", raising=False)
+        assert _check_ha_available() is False
+
+    def test_available_with_token(self, monkeypatch):
+        monkeypatch.setenv("HASS_TOKEN", "eyJ0eXAiOiJKV1Q")
+        assert _check_ha_available() is True
+
+    def test_empty_token_is_unavailable(self, monkeypatch):
+        monkeypatch.setenv("HASS_TOKEN", "")
+        assert _check_ha_available() is False
+
+
+# ---------------------------------------------------------------------------
+# Auth headers
+# ---------------------------------------------------------------------------
+
+
+class TestGetHeaders:
+    def test_bearer_token_format(self, monkeypatch):
+        monkeypatch.setattr("tools.homeassistant_tool._HASS_TOKEN", "my-secret-token")
+        headers = _get_headers()
+        assert headers["Authorization"] == "Bearer my-secret-token"
+        assert headers["Content-Type"] == "application/json"
+
+
+# ---------------------------------------------------------------------------
+# Registry integration
+# ---------------------------------------------------------------------------
+
+
+class TestRegistration:
+    def test_tools_registered_in_registry(self):
+        from tools.registry import registry
+
+        names = registry.get_all_tool_names()
+        assert "ha_list_entities" in names
+        assert "ha_get_state" in names
+        assert "ha_call_service" in names
+
+    def test_tools_in_homeassistant_toolset(self):
+        from tools.registry import registry
+
+        toolset_map = registry.get_tool_to_toolset_map()
+        for tool in ("ha_list_entities", "ha_get_state", "ha_call_service"):
+            assert toolset_map[tool] == "homeassistant"
+
+    def test_check_fn_gates_availability(self, monkeypatch):
+        """Registry should exclude HA tools when HASS_TOKEN is not set."""
+        from tools.registry import registry
+
+        monkeypatch.delenv("HASS_TOKEN", raising=False)
+        defs = registry.get_definitions({"ha_list_entities", "ha_get_state", "ha_call_service"})
+        assert len(defs) == 0
+
+    def test_check_fn_includes_when_token_set(self, monkeypatch):
+        """Registry should include HA tools when HASS_TOKEN is set."""
+        from tools.registry import registry
+
+        monkeypatch.setenv("HASS_TOKEN", "test-token")
+        defs = registry.get_definitions({"ha_list_entities", "ha_get_state", "ha_call_service"})
+        assert len(defs) == 3