feat: add realtime GNSS monitor with telemetry websocket

backend/tests/mqtt/test_parser_worker.py

@@ -85,3 +85,65 @@ def test_worker_marks_failed_without_retry_schedule(monkeypatch) -> None:
 
 def test_schema_excludes_terminal_observation_event_table() -> None:
     assert "terminal_observation_event" not in SQLModel.metadata.tables
+
+
+def test_ingest_and_parse_real_nmea_sample() -> None:
+    from pathlib import Path
+
+    sample_path = Path(__file__).parent / "nmea.txt"
+    payload = sample_path.read_bytes()
+
+    with _session() as session:
+        raw = insert_raw_message(
+            session=session,
+            device_id="device-real-sample",
+            topic="terminal/device-real-sample/raw",
+            payload=payload,
+            qos=1,
+            retain=False,
+        )
+
+        processed = process_pending_batch(session=session, batch_size=10)
+        assert processed == 1
+
+        refreshed = session.get(TerminalMessageRaw, raw.id)
+        assert refreshed is not None
+        assert refreshed.parsed_at is not None
+        assert refreshed.parse_error is None
+
+        state = session.get(TerminalDeviceState, "device-real-sample")
+        assert state is not None
+        assert state.lat is not None
+        assert state.lon is not None
+
+
+def test_worker_builds_satellite_distribution_summary() -> None:
+    payload = (
+        b"$GNGGA,123519,3723.2475,N,12158.3416,W,4,12,0.8,10.0,M,-25.0,M,,*65\r\n"
+        b"$GPGSA,A,3,02,05,12,,,,,,,,,,1.50,0.90,1.20*00\r\n"
+        b"$GPGSV,1,1,04,02,17,213,40,05,29,121,37,12,66,314,44,25,14,048,39*71\r\n"
+    )
+
+    with _session() as session:
+        insert_raw_message(
+            session=session,
+            device_id="device-gsv",
+            topic="terminal/device-gsv/raw",
+            payload=payload,
+            qos=1,
+            retain=False,
+        )
+
+        processed = process_pending_batch(session=session, batch_size=10)
+
+        assert processed == 1
+        state = session.get(TerminalDeviceState, "device-gsv")
+        assert state is not None
+        assert state.fix_status == "4"
+        summary = state.satellite_signal_summary
+        assert summary is not None
+        assert summary["satellites_in_view"] == 4
+        assert summary["snr_values"] == [40, 37, 44, 39]
+        assert summary["used_satellite_ids"] == ["02", "05", "12"]
+        assert summary["constellations"]["GPS"]["count"] == 4
+        assert summary["constellations"]["GPS"]["used_in_navigation"] == 3