fix: repair 10 stale tests in test_mqtt_handler.py and test_node_sweeper.py

All 10 failures were tests that had drifted behind the product code, not
regressions in it. Diagnosed each individually:

test_mqtt_handler.py:
- test_checkin_creates_new_node, test_checkin_new_node_defaults_lat_lon:
  unpacked 4 positional args from doc_set.call_args[0], but
  fstore.doc_set(collection, doc_id, data, merge=False) always passes
  merge as a kwarg, so only 3 positional args are ever recorded. Fixed
  the unpack to 3.
- test_call_start_creates_call_doc, test_call_start_uses_now_when_started_at_missing:
  mocked fstore.doc_get, but _on_call_start looks the node up via the
  cached fstore.doc_get_cached (added when Firestore reads were cut to
  stay in the free tier). The unmocked doc_get_cached returned a bare
  MagicMock, which isn't awaitable. Mocked doc_get_cached instead; also
  fixed the same 4-vs-3 positional-arg unpack on doc_set's merge=False call.
- test_call_end_updates_status_and_times, test_call_end_sets_audio_url_when_present:
  mocked fstore.doc_update, but _on_call_end now writes via
  fstore.doc_set(merge=True) (see the "Fix Upload 404 warning" commit —
  doc_update raised "No document to update" when call_end arrived before
  call_start). Also calls doc_get_cached to stamp org_id. Mocked
  doc_get_cached and asserted against doc_set instead of doc_update.

test_node_sweeper.py:
- test_stale_online_node_marked_offline, test_stale_recording_node_marked_offline,
  test_tz_naive_last_seen_is_handled, test_only_stale_nodes_updated_in_batch:
  _sweep() now calls app.routers.tokens.release_token(node_id) for every
  node it marks offline (added in 2a690ec, the PulseAudio/Discord-token
  work). These tests never mocked it, so the module-level
  patch("asyncio.to_thread", ...) meant for the node-query call leaked
  into release_token's own internal to_thread call, feeding it raw node
  dicts where it expected Firestore doc snapshots with .id — hence
  "AttributeError: 'dict' object has no attribute 'id'". Patched
  app.routers.tokens.release_token directly (it's imported inline inside
  _sweep, so patching the source module works); the batch test also now
  asserts release_token fires for exactly the two nodes that went offline.

No product code changed — app/internal/mqtt_handler.py, app/routers/tokens.py,
and app/internal/node_sweeper.py all behave as intended. This was pure test
drift across two unrelated feature additions (Firestore-read caching,
Discord-token release-on-offline) that landed without their tests being
updated.

93 passed, 0 failed.

Closes logan/server-26#10.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

drb-c2-core/tests/test_mqtt_handler.py

@@ -67,7 +67,9 @@ async def test_checkin_creates_new_node(handler):
         )
 
     mock_fstore.doc_set.assert_called_once()
-    _, _, doc, _ = mock_fstore.doc_set.call_args[0]
+    # doc_set(collection, doc_id, data, merge=False) — merge is passed as a
+    # kwarg in mqtt_handler.py, so only 3 positional args land in call_args[0].
+    _, _, doc = mock_fstore.doc_set.call_args[0]
     assert doc["node_id"] == "new-node"
     assert doc["name"] == "Pi Zero W"
     assert doc["status"] == "unconfigured"
@@ -84,7 +86,7 @@ async def test_checkin_new_node_defaults_lat_lon(handler):
 
         await handler._handle_checkin("new-node", {})
 
-    _, _, doc, _ = mock_fstore.doc_set.call_args[0]
+    _, _, doc = mock_fstore.doc_set.call_args[0]
     assert doc["lat"] == 0.0
     assert doc["lon"] == 0.0
 
@@ -200,13 +202,17 @@ async def test_call_start_creates_call_doc(handler):
     }
 
     with patch("app.internal.mqtt_handler.fstore") as mock_fstore:
-        mock_fstore.doc_get = AsyncMock(return_value=node)
+        # _on_call_start looks the node up via doc_get_cached (cached read,
+        # added to cut Firestore read volume — see doc_get_cached in
+        # app/internal/firestore.py), not the uncached doc_get.
+        mock_fstore.doc_get_cached = AsyncMock(return_value=node)
         mock_fstore.doc_set = AsyncMock()
 
         await handler._on_call_start("node-01", payload)
 
     mock_fstore.doc_set.assert_called_once()
-    _, _, doc, _ = mock_fstore.doc_set.call_args[0]
+    # doc_set(collection, doc_id, data, merge=False) — merge is a kwarg here too.
+    _, _, doc = mock_fstore.doc_set.call_args[0]
     assert doc["call_id"] == "call-abc123"
     assert doc["node_id"] == "node-01"
     assert doc["system_id"] == "sys-001"
@@ -233,12 +239,12 @@ async def test_call_start_uses_now_when_started_at_missing(handler):
     payload = {"call_id": "call-xyz", "tgid": 99}
 
     with patch("app.internal.mqtt_handler.fstore") as mock_fstore:
-        mock_fstore.doc_get = AsyncMock(return_value=node)
+        mock_fstore.doc_get_cached = AsyncMock(return_value=node)
         mock_fstore.doc_set = AsyncMock()
 
         await handler._on_call_start("node-01", payload)
 
-    _, _, doc, _ = mock_fstore.doc_set.call_args[0]
+    _, _, doc = mock_fstore.doc_set.call_args[0]
     assert doc["started_at"] is not None
 
 
@@ -250,11 +256,17 @@ async def test_call_end_updates_status_and_times(handler):
     }
 
     with patch("app.internal.mqtt_handler.fstore") as mock_fstore:
-        mock_fstore.doc_update = AsyncMock()
+        # _on_call_end writes via doc_set(merge=True) now, not doc_update — see
+        # the "Fix Upload 404 warning" commit: doc_update raised "No document
+        # to update" when call_end raced ahead of call_start, so it was
+        # switched to a merging doc_set. It also reads the node via the
+        # cached doc_get_cached to stamp org_id.
+        mock_fstore.doc_get_cached = AsyncMock(return_value=None)
+        mock_fstore.doc_set = AsyncMock()
 
         await handler._on_call_end("node-01", payload)
 
-    updates = mock_fstore.doc_update.call_args[0][2]
+    updates = mock_fstore.doc_set.call_args[0][2]
     assert updates["status"] == "ended"
     assert updates["ended_at"] is not None
 
@@ -268,11 +280,12 @@ async def test_call_end_sets_audio_url_when_present(handler):
     }
 
     with patch("app.internal.mqtt_handler.fstore") as mock_fstore:
-        mock_fstore.doc_update = AsyncMock()
+        mock_fstore.doc_get_cached = AsyncMock(return_value=None)
+        mock_fstore.doc_set = AsyncMock()
 
         await handler._on_call_end("node-01", payload)
 
-    updates = mock_fstore.doc_update.call_args[0][2]
+    updates = mock_fstore.doc_set.call_args[0][2]
     assert updates["audio_url"] == "https://storage.example.com/call.mp3"