优化传感器布置算法，修复数据库更新逻辑

tests/unit/test_scada_repository.py

@@ -0,0 +1,87 @@
+from datetime import datetime, timezone
+import importlib.util
+from pathlib import Path
+
+import pytest
+
+
+def _load_scada_repository():
+    module_path = (
+        Path(__file__).resolve().parents[2]
+        / "app"
+        / "infra"
+        / "db"
+        / "timescaledb"
+        / "repositories"
+        / "scada.py"
+    )
+    spec = importlib.util.spec_from_file_location("tests_scada_repo_under_test", module_path)
+    module = importlib.util.module_from_spec(spec)
+    assert spec and spec.loader
+    spec.loader.exec_module(module)
+    return module.ScadaRepository
+
+
+class _FakeCursor:
+    def __init__(self, initial_rowcount: int):
+        self.initial_rowcount = initial_rowcount
+        self.rowcount = 0
+        self.calls: list[tuple[str, tuple]] = []
+
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc, tb):
+        return False
+
+    async def execute(self, query, params):
+        self.calls.append((str(query), params))
+        if len(self.calls) == 1:
+            self.rowcount = self.initial_rowcount
+        else:
+            self.rowcount = 1
+
+
+class _FakeConnection:
+    def __init__(self, initial_rowcount: int):
+        self.cursor_instance = _FakeCursor(initial_rowcount)
+
+    def cursor(self):
+        return self.cursor_instance
+
+
+@pytest.mark.asyncio
+async def test_update_scada_field_inserts_when_update_hits_no_rows():
+    ScadaRepository = _load_scada_repository()
+    conn = _FakeConnection(initial_rowcount=0)
+    point_time = datetime(2026, 1, 1, 0, 0, tzinfo=timezone.utc)
+
+    await ScadaRepository.update_scada_field(
+        conn,
+        point_time,
+        "170490",
+        "cleaned_value",
+        26.5,
+    )
+
+    assert len(conn.cursor_instance.calls) == 2
+    assert "UPDATE scada.scada_data SET" in conn.cursor_instance.calls[0][0]
+    assert "INSERT INTO scada.scada_data" in conn.cursor_instance.calls[1][0]
+
+
+@pytest.mark.asyncio
+async def test_update_scada_field_skips_insert_when_update_succeeds():
+    ScadaRepository = _load_scada_repository()
+    conn = _FakeConnection(initial_rowcount=1)
+    point_time = datetime(2026, 1, 1, 0, 0, tzinfo=timezone.utc)
+
+    await ScadaRepository.update_scada_field(
+        conn,
+        point_time,
+        "170490",
+        "cleaned_value",
+        26.5,
+    )
+
+    assert len(conn.cursor_instance.calls) == 1
+    assert "UPDATE scada.scada_data SET" in conn.cursor_instance.calls[0][0]