add unsubscribe test

Remove characteristic in GATT Client unsubscribe() if it's the last subscriber

bumble/gatt_client.py

@@ -898,6 +898,12 @@ class Client:
                 ) and subscriber in subscribers:
                     subscribers.remove(subscriber)
 
+                    # The characteristic itself is added as subscriber. If it is the
+                    # last remaining subscriber, we remove it, such that the clean up
+                    # works correctly. Otherwise the CCCD never is set back to 0.
+                    if len(subscribers) == 1 and characteristic in subscribers:
+                        subscribers.remove(characteristic)
+
                     # Cleanup if we removed the last one
                     if not subscribers:
                         del subscriber_set[characteristic.handle]

bumble/profiles/bap.py

@@ -102,6 +102,7 @@ class ContextType(enum.IntFlag):
 
     # fmt: off
     PROHIBITED       = 0x0000
+    UNSPECIFIED      = 0x0001
     CONVERSATIONAL   = 0x0002
     MEDIA            = 0x0004
     GAME             = 0x0008

tests/gatt_test.py

@@ -851,7 +851,12 @@ async def test_unsubscribe():
     await async_barrier()
     mock1.assert_called_once_with(ANY, True, False)
 
-    await c2.subscribe()
+    assert len(server.gatt_server.subscribers) == 1
+
+    def callback(_):
+        pass
+
+    await c2.subscribe(callback)
     await async_barrier()
     mock2.assert_called_once_with(ANY, True, False)
 
@@ -861,10 +866,16 @@ async def test_unsubscribe():
     mock1.assert_called_once_with(ANY, False, False)
 
     mock2.reset_mock()
-    await c2.unsubscribe()
+    await c2.unsubscribe(callback)
     await async_barrier()
     mock2.assert_called_once_with(ANY, False, False)
 
+    # All CCCDs should be zeros now
+    assert list(server.gatt_server.subscribers.values())[0] == {
+        c1.handle: bytes([0, 0]),
+        c2.handle: bytes([0, 0]),
+    }
+
     mock1.reset_mock()
     await c1.unsubscribe()
     await async_barrier()