test(e2e): add negative-input tests for ha_get_history and ha_get_automation_traces (homeassistant-ai#945)

* test(e2e): add negative-input tests for ha_get_history and ha_get_automation_traces

Covers three genuinely uncovered paths identified via source-level analysis
and cross-checked against the full test suite (unit + E2E).

ha_get_history — two new cases in workflows/core/test_history.py:
- entity_ids="": single-string branch → entity_id_list=[""] → no pre-flight guard
  → WS call → HA valid_entity_id("")=False → Command failed → INTERNAL_ERROR
- entity_ids=[]: list branch → if-not-entity_id_list → VALIDATION_MISSING_PARAMETER
  (no WS call)

ha_get_automation_traces — new file workflows/automation/test_traces_negative.py:
- automation_id="sensor.some_entity": domain-guard (tools_traces.py) rejects
  non-automation/script prefix → VALIDATION_INVALID_PARAMETER (no WS call)

No prior hard coverage in unit (57 files) or E2E suite for any of these paths.
Verified: tools_history.py, tools_traces.py, websocket_client.py, helpers.py.

* fix(test): address review feedback on homeassistant-ai#945

- Move ha_get_automation_traces test into existing test_traces.py
- Remove standalone test_traces_negative.py (new file was wrong)
- Remove @pytest.mark.asyncio (asyncio_mode = auto)
- Add type hints: mcp_client: Any, -> None
- Use result directly (no data wrapper on safe_call_tool results)
- Shorten docstrings to one sentence each

* fix(test): sort imports per ruff I001

* fix(test): remove asyncio decorator and shorten docstrings per review

---------

Co-authored-by: Patch76 <patch76@local>
Co-authored-by: Patch76 <patch76@users.noreply.github.com>

Author: Patch76

tests/src/e2e/workflows/automation/test_traces.py

@@ -6,12 +6,14 @@
 """
 
 import logging
+from typing import Any
 
 import pytest
 
 from ...utilities.assertions import (
     assert_mcp_success,
     parse_mcp_result,
+    safe_call_tool,
 )
 from ...utilities.wait_helpers import wait_for_condition
 
@@ -337,3 +339,17 @@ async def check_traces():
         assert trace_count > 0, (
             f"Expected at least 1 trace after running script, got {trace_count}"
         )
+
+@pytest.mark.automation
+class TestGetAutomationTracesNegativeInputs:
+    """Negative-input tests for ha_get_automation_traces."""
+
+    async def test_wrong_domain_prefix_rejected(self, mcp_client: Any) -> None:
+        """Rejects an entity ID that does not belong to a supported domain."""
+        result = await safe_call_tool(
+            mcp_client,
+            "ha_get_automation_traces",
+            {"automation_id": "sensor.some_entity"},
+        )
+        assert result["success"] is False
+        assert result["error"]["code"] == "VALIDATION_INVALID_PARAMETER"

tests/src/e2e/workflows/core/test_history.py

@@ -7,6 +7,7 @@
 
 import logging
 from datetime import UTC, datetime, timedelta
+from typing import Any
 
 import pytest
 
@@ -571,7 +572,6 @@ async def test_get_statistics_entity_without_state_class(self, mcp_client):
             logger.info("Properly returned error for entity without state_class")
 
 
-@pytest.mark.asyncio
 @pytest.mark.core
 async def test_get_history_query_params_in_response(mcp_client):
     """Test that query parameters are included in response."""
@@ -603,3 +603,28 @@ async def test_get_history_query_params_in_response(mcp_client):
         assert params.get("limit") == 10, f"limit mismatch: {params}"
     else:
         logger.info("query_params not in response (may be by design)")
+
+
+@pytest.mark.core
+class TestGetHistoryNegativeInputs:
+    """Negative-input tests for ha_get_history."""
+
+    async def test_empty_string_entity_id_rejected(self, mcp_client: Any) -> None:
+        """Rejects an invalid entity ID that cannot be resolved by the WebSocket handler."""
+        result = await safe_call_tool(
+            mcp_client,
+            "ha_get_history",
+            {"entity_ids": "", "start_time": "1h"},
+        )
+        assert result["success"] is False
+        assert result["error"]["code"] == "INTERNAL_ERROR"
+
+    async def test_empty_list_entity_ids_rejected(self, mcp_client: Any) -> None:
+        """Rejects an empty list before any network call is made."""
+        result = await safe_call_tool(
+            mcp_client,
+            "ha_get_history",
+            {"entity_ids": [], "start_time": "1h"},
+        )
+        assert result["success"] is False
+        assert result["error"]["code"] == "VALIDATION_MISSING_PARAMETER"