add support for alternate settings

bumble/att.py

@@ -700,26 +700,16 @@ class Attribute(EventEmitter):
         else:
             self.value = value
 
-    def encode_value(self, value):
-        return value
-
-    def decode_value(self, value_bytes):
-        return value_bytes
-
     def read_value(self, connection):
         if read := getattr(self.value, 'read', None):
             try:
-                value = read(connection)
+                return read(connection)
             except ATT_Error as error:
                 raise ATT_Error(error_code=error.error_code, att_handle=self.handle)
         else:
-            value = self.value
-
-        return self.encode_value(value)
-
-    def write_value(self, connection, value_bytes):
-        value = self.decode_value(value_bytes)
+            return self.value
 
+    def write_value(self, connection, value):
         if write := getattr(self.value, 'write', None):
             try:
                 write(connection, value)
@@ -731,11 +721,7 @@ class Attribute(EventEmitter):
         self.emit('write', connection, value)
 
     def __repr__(self):
-        if type(self.value) is bytes:
-            value_str = self.value.hex()
-        else:
-            value_str = str(self.value)
-        if value_str:
+        if len(self.value) > 0:
             value_string = f', value={self.value.hex()}'
         else:
             value_string = ''

bumble/device.py

@@ -1210,17 +1210,17 @@ class Device(CompositeEventEmitter):
     def add_services(self, services):
         self.gatt_server.add_services(services)
 
-    async def notify_subscriber(self, connection, attribute, value=None, force=False):
-        await self.gatt_server.notify_subscriber(connection, attribute, value, force)
+    async def notify_subscriber(self, connection, attribute, force=False):
+        await self.gatt_server.notify_subscriber(connection, attribute, force)
 
-    async def notify_subscribers(self, attribute, value=None, force=False):
-        await self.gatt_server.notify_subscribers(attribute, value, force)
+    async def notify_subscribers(self, attribute, force=False):
+        await self.gatt_server.notify_subscribers(attribute, force)
 
-    async def indicate_subscriber(self, connection, attribute, value=None, force=False):
-        await self.gatt_server.indicate_subscriber(connection, attribute, value, force)
+    async def indicate_subscriber(self, connection, attribute, force=False):
+        await self.gatt_server.indicate_subscriber(connection, attribute, force)
 
-    async def indicate_subscribers(self, attribute, value=None, force=False):
-        await self.gatt_server.indicate_subscribers(attribute, value, force)
+    async def indicate_subscribers(self, attribute):
+        await self.gatt_server.indicate_subscribers(attribute)
 
     @host_event_handler
     def on_connection(self, connection_handle, transport, peer_address, peer_resolvable_address, role, connection_parameters):

bumble/gatt.py

@@ -303,7 +303,6 @@ class CharacteristicAdapter:
     '''
     def __init__(self, characteristic):
         self.wrapped_characteristic = characteristic
-        self.subscribers = {}  # Map from subscriber to proxy subscriber
 
         if (
             asyncio.iscoroutinefunction(characteristic.read_value) and
@@ -318,21 +317,11 @@ class CharacteristicAdapter:
         if hasattr(self.wrapped_characteristic, 'subscribe'):
             self.subscribe = self.wrapped_subscribe
 
-        if hasattr(self.wrapped_characteristic, 'unsubscribe'):
-            self.unsubscribe = self.wrapped_unsubscribe
-
     def __getattr__(self, name):
         return getattr(self.wrapped_characteristic, name)
 
     def __setattr__(self, name, value):
-        if name in {
-            'wrapped_characteristic',
-            'subscribers',
-            'read_value',
-            'write_value',
-            'subscribe',
-            'unsubscribe'
-        }:
+        if name in {'wrapped_characteristic', 'read_value', 'write_value', 'subscribe'}:
             super().__setattr__(name, value)
         else:
             setattr(self.wrapped_characteristic, name, value)
@@ -356,26 +345,9 @@ class CharacteristicAdapter:
         return value
 
     def wrapped_subscribe(self, subscriber=None):
-        if subscriber is not None:
-            if subscriber in self.subscribers:
-                # We already have a proxy subscriber
-                subscriber = self.subscribers[subscriber]
-            else:
-                # Create and register a proxy that will decode the value
-                original_subscriber = subscriber
-
-                def on_change(value):
-                    original_subscriber(self.decode_value(value))
-                self.subscribers[subscriber] = on_change
-                subscriber = on_change
-
-        return self.wrapped_characteristic.subscribe(subscriber)
-
-    def wrapped_unsubscribe(self, subscriber=None):
-        if subscriber in self.subscribers:
-            subscriber = self.subscribers.pop(subscriber)
-
-        return self.wrapped_characteristic.unsubscribe(subscriber)
+        return self.wrapped_characteristic.subscribe(
+            None if subscriber is None else lambda value: subscriber(self.decode_value(value))
+        )
 
     def __str__(self):
         wrapped = str(self.wrapped_characteristic)

bumble/gatt_client.py

@@ -58,16 +58,10 @@ class AttributeProxy(EventEmitter):
         self.type             = attribute_type
 
     async def read_value(self, no_long_read=False):
-        return self.decode_value(await self.client.read_value(self.handle, no_long_read))
+        return await self.client.read_value(self.handle, no_long_read)
 
     async def write_value(self, value, with_response=False):
-        return await self.client.write_value(self.handle, self.encode_value(value), with_response)
-
-    def encode_value(self, value):
-        return value
-
-    def decode_value(self, value_bytes):
-        return value_bytes
+        return await self.client.write_value(self.handle, value, with_response)
 
     def __str__(self):
         return f'Attribute(handle=0x{self.handle:04X}, type={self.uuid})'
@@ -104,7 +98,6 @@ class CharacteristicProxy(AttributeProxy):
         self.properties             = properties
         self.descriptors            = []
         self.descriptors_discovered = False
-        self.subscribers            = {}  # Map from subscriber to proxy subscriber
 
     def get_descriptor(self, descriptor_type):
         for descriptor in self.descriptors:
@@ -115,25 +108,9 @@ class CharacteristicProxy(AttributeProxy):
         return await self.client.discover_descriptors(self)
 
     async def subscribe(self, subscriber=None):
-        if subscriber is not None:
-            if subscriber in self.subscribers:
-                # We already have a proxy subscriber
-                subscriber = self.subscribers[subscriber]
-            else:
-                # Create and register a proxy that will decode the value
-                original_subscriber = subscriber
-
-                def on_change(value):
-                    original_subscriber(self.decode_value(value))
-                self.subscribers[subscriber] = on_change
-                subscriber = on_change
-
         return await self.client.subscribe(self, subscriber)
 
     async def unsubscribe(self, subscriber=None):
-        if subscriber in self.subscribers:
-            subscriber = self.subscribers.pop(subscriber)
-
         return await self.client.unsubscribe(self, subscriber)
 
     def __str__(self):
@@ -593,18 +570,12 @@ class Client:
                 subscribers = subscriber_set.get(characteristic.handle, [])
                 if subscriber in subscribers:
                     subscribers.remove(subscriber)
-
-                    # Cleanup if we removed the last one
-                    if not subscribers:
-                        subscriber_set.remove(characteristic.handle)
         else:
             # Remove all subscribers for this attribute from the sets!
             self.notification_subscribers.pop(characteristic.handle, None)
             self.indication_subscribers.pop(characteristic.handle, None)
 
-        if not self.notification_subscribers and not self.indication_subscribers:
-            # No more subscribers left
-            await self.write_value(cccd, b'\x00\x00', with_response=True)
+        await self.write_value(cccd, b'\x00\x00', with_response=True)
 
     async def read_value(self, attribute, no_long_read=False):
         '''

bumble/gatt_server.py

@@ -169,7 +169,7 @@ class Server(EventEmitter):
         logger.debug(f'GATT Response from server: [0x{connection.handle:04X}] {response}')
         self.send_gatt_pdu(connection.handle, response.to_bytes())
 
-    async def notify_subscriber(self, connection, attribute, value=None, force=False):
+    async def notify_subscriber(self, connection, attribute, force=False):
         # Check if there's a subscriber
         if not force:
             subscribers = self.subscribers.get(connection.handle)
@@ -184,8 +184,8 @@ class Server(EventEmitter):
                 logger.debug(f'not notifying, cccd={cccd.hex()}')
                 return
 
-        # Get or encode the value
-        value = attribute.read_value(connection) if value is None else attribute.encode_value(value)
+        # Get the value
+        value = attribute.read_value(connection)
 
         # Truncate if needed
         mtu = self.get_mtu(connection)
@@ -198,9 +198,27 @@ class Server(EventEmitter):
             attribute_value  = value
         )
         logger.debug(f'GATT Notify from server: [0x{connection.handle:04X}] {notification}')
-        self.send_gatt_pdu(connection.handle, bytes(notification))
+        self.send_gatt_pdu(connection.handle, notification.to_bytes())
 
-    async def indicate_subscriber(self, connection, attribute, value=None, force=False):
+    async def notify_subscribers(self, attribute, force=False):
+        # Get all the connections for which there's at least one subscription
+        connections = [
+            connection for connection in [
+                self.device.lookup_connection(connection_handle)
+                for (connection_handle, subscribers) in self.subscribers.items()
+                if force or subscribers.get(attribute.handle)
+            ]
+            if connection is not None
+        ]
+
+        # Notify for each connection
+        if connections:
+            await asyncio.wait([
+                self.notify_subscriber(connection, attribute, force)
+                for connection in connections
+            ])
+
+    async def indicate_subscriber(self, connection, attribute, force=False):
         # Check if there's a subscriber
         if not force:
             subscribers = self.subscribers.get(connection.handle)
@@ -215,8 +233,8 @@ class Server(EventEmitter):
                 logger.debug(f'not indicating, cccd={cccd.hex()}')
                 return
 
-        # Get or encode the value
-        value = attribute.read_value(connection) if value is None else attribute.encode_value(value)
+        # Get the value
+        value = attribute.read_value(connection)
 
         # Truncate if needed
         mtu = self.get_mtu(connection)
@@ -246,31 +264,24 @@ class Server(EventEmitter):
             finally:
                 self.pending_confirmations[connection.handle] = None
 
-    async def notify_or_indicate_subscribers(self, indicate, attribute, value=None, force=False):
+    async def indicate_subscribers(self, attribute):
         # Get all the connections for which there's at least one subscription
         connections = [
             connection for connection in [
                 self.device.lookup_connection(connection_handle)
                 for (connection_handle, subscribers) in self.subscribers.items()
-                if force or subscribers.get(attribute.handle)
+                if subscribers.get(attribute.handle)
             ]
             if connection is not None
         ]
 
-        # Indicate or notify for each connection
+        # Indicate for each connection
         if connections:
-            coroutine = self.indicate_subscriber if indicate else self.notify_subscriber
             await asyncio.wait([
-                asyncio.create_task(coroutine(connection, attribute, value, force))
+                self.indicate_subscriber(connection, attribute)
                 for connection in connections
             ])
 
-    async def notify_subscribers(self, attribute, value=None, force=False):
-        return await self.notify_or_indicate_subscribers(False, attribute, value, force)
-
-    async def indicate_subscribers(self, attribute, value=None, force=False):
-        return await self.notify_or_indicate_subscribers(True, attribute, value, force)
-
     def on_disconnection(self, connection):
         if connection.handle in self.mtus:
             del self.mtus[connection.handle]

bumble/transport/usb.py

@@ -56,18 +56,19 @@ async def open_usb_transport(spec):
 
     USB_RECIPIENT_DEVICE                             = 0x00
     USB_REQUEST_TYPE_CLASS                           = 0x01 << 5
-    USB_ENDPOINT_EVENTS_IN                           = 0x81
-    USB_ENDPOINT_ACL_IN                              = 0x82
-    USB_ENDPOINT_ACL_OUT                             = 0x02
     USB_DEVICE_CLASS_WIRELESS_CONTROLLER             = 0xE0
     USB_DEVICE_SUBCLASS_RF_CONTROLLER                = 0x01
     USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER = 0x01
+    USB_ENDPOINT_TRANSFER_TYPE_BULK                  = 0x02
+    USB_ENDPOINT_TRANSFER_TYPE_INTERRUPT             = 0x03
+    USB_ENDPOINT_IN                                  = 0x80
 
     READ_SIZE = 1024
 
     class UsbPacketSink:
-        def __init__(self, device):
+        def __init__(self, device, acl_out):
             self.device      = device
+            self.acl_out     = acl_out
             self.transfer    = device.getTransfer()
             self.packets     = collections.deque()  # Queue of packets waiting to be sent
             self.loop        = asyncio.get_running_loop()
@@ -116,7 +117,7 @@ async def open_usb_transport(spec):
             packet_type = packet[0]
             if packet_type == hci.HCI_ACL_DATA_PACKET:
                 self.transfer.setBulk(
-                    USB_ENDPOINT_ACL_OUT,
+                    self.acl_out,
                     packet[1:],
                     callback=self.on_packet_sent
                 )
@@ -152,10 +153,12 @@ async def open_usb_transport(spec):
                     logger.debug('OUT transfer likely already completed')
 
     class UsbPacketSource(asyncio.Protocol, ParserSource):
-        def __init__(self, context, device):
+        def __init__(self, context, device, acl_in, events_in):
             super().__init__()
             self.context         = context
             self.device          = device
+            self.acl_in          = acl_in
+            self.events_in       = events_in
             self.loop            = asyncio.get_running_loop()
             self.queue           = asyncio.Queue()
             self.closed          = False
@@ -172,7 +175,7 @@ async def open_usb_transport(spec):
             # Set up transfer objects for input
             self.events_in_transfer = device.getTransfer()
             self.events_in_transfer.setInterrupt(
-                USB_ENDPOINT_EVENTS_IN,
+                self.events_in,
                 READ_SIZE,
                 callback=self.on_packet_received,
                 user_data=hci.HCI_EVENT_PACKET
@@ -181,7 +184,7 @@ async def open_usb_transport(spec):
 
             self.acl_in_transfer = device.getTransfer()
             self.acl_in_transfer.setBulk(
-                USB_ENDPOINT_ACL_IN,
+                self.acl_in,
                 READ_SIZE,
                 callback=self.on_packet_received,
                 user_data=hci.HCI_ACL_DATA_PACKET
@@ -248,7 +251,7 @@ async def open_usb_transport(spec):
             await self.event_loop_done
 
     class UsbTransport(Transport):
-        def __init__(self, context, device, interface, source, sink):
+        def __init__(self, context, device, interface, setting, source, sink):
             super().__init__(source, sink)
             self.context   = context
             self.device    = device
@@ -257,6 +260,10 @@ async def open_usb_transport(spec):
             # Get exclusive access
             device.claimInterface(interface)
 
+            # Set the alternate setting if not the default
+            if setting != 0:
+                device.setInterfaceAltSetting(interface, setting)
+
             # The source and sink can now start
             source.start()
             sink.start()
@@ -313,10 +320,63 @@ async def open_usb_transport(spec):
             raise ValueError('device not found')
 
         logger.debug(f'USB Device: {found}')
-        device = found.open()
 
-        # Use the first interface
-        interface = 0
+        # Look for the first interface with the right class and endpoints
+        def find_endpoints(device):
+            for (configuration_index, configuration) in enumerate(device):
+                interface = None
+                for interface in configuration:
+                    setting = None
+                    for setting in interface:
+                        if (
+                            setting.getClass() != USB_DEVICE_CLASS_WIRELESS_CONTROLLER or
+                            setting.getSubClass() != USB_DEVICE_SUBCLASS_RF_CONTROLLER or
+                            setting.getProtocol() != USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
+                        ):
+                            continue
+
+                        events_in = None
+                        acl_in    = None
+                        acl_out   = None
+                        for endpoint in setting:
+                            attributes = endpoint.getAttributes()
+                            address    = endpoint.getAddress()
+                            if attributes & 0x03 == USB_ENDPOINT_TRANSFER_TYPE_BULK:
+                                if address & USB_ENDPOINT_IN and acl_in is None:
+                                    acl_in = address
+                                elif acl_out is None:
+                                    acl_out = address
+                            elif attributes & 0x03 == USB_ENDPOINT_TRANSFER_TYPE_INTERRUPT:
+                                if address & USB_ENDPOINT_IN and events_in is None:
+                                    events_in = address
+
+                        # Return if we found all 3 endpoints
+                        if acl_in is not None and acl_out is not None and events_in is not None:
+                            return (
+                                configuration_index + 1,
+                                setting.getNumber(),
+                                setting.getAlternateSetting(),
+                                acl_in,
+                                acl_out,
+                                events_in
+                            )
+                        else:
+                            logger.debug(f'skipping configuration {configuration_index + 1} / interface {setting.getNumber()}')
+
+        endpoints = find_endpoints(found)
+        if endpoints is None:
+            raise ValueError('no compatible interface found for device')
+        (configuration, interface, setting, acl_in, acl_out, events_in) = endpoints
+        logger.debug(
+            f'selected endpoints: configuration={configuration}, '
+            f'interface={interface}, '
+            f'setting={setting}, '
+            f'acl_in=0x{acl_in:02X}, '
+            f'acl_out=0x{acl_out:02X}, '
+            f'events_in=0x{events_in:02X}, '
+        )
+
+        device = found.open()
 
         # Detach the kernel driver if supported and needed
         if usb1.hasCapability(usb1.CAP_SUPPORTS_DETACH_KERNEL_DRIVER):
@@ -329,21 +389,21 @@ async def open_usb_transport(spec):
 
         # Set the configuration if needed
         try:
-            configuration = device.getConfiguration()
-            logger.debug(f'current configuration = {configuration}')
+            current_configuration = device.getConfiguration()
+            logger.debug(f'current configuration = {current_configuration}')
         except usb1.USBError:
-            configuration = 0
+            current_configuration = 0
 
-        if configuration != 1:
+        if current_configuration != configuration:
             try:
-                logger.debug('setting configuration 1')
-                device.setConfiguration(1)
+                logger.debug(f'setting configuration {configuration}')
+                device.setConfiguration(configuration)
             except usb1.USBError:
-                logger.warning('failed to set configuration 1')
+                logger.warning('failed to set configuration')
 
-        source = UsbPacketSource(context, device)
-        sink   = UsbPacketSink(device)
-        return UsbTransport(context, device, interface, source, sink)
+        source = UsbPacketSource(context, device, acl_in, events_in)
+        sink   = UsbPacketSink(device, acl_out)
+        return UsbTransport(context, device, interface, setting, source, sink)
     except usb1.USBError as error:
         logger.warning(color(f'!!! failed to open USB device: {error}', 'red'))
         context.close()

tests/gatt_test.py

@@ -22,7 +22,6 @@ import struct
 import pytest
 
 from bumble.controller import Controller
-from bumble.gatt_client import CharacteristicProxy
 from bumble.link import LocalLink
 from bumble.device import Device, Peer
 from bumble.host import Host
@@ -54,29 +53,29 @@ def basic_check(x):
     parsed = ATT_PDU.from_bytes(pdu)
     x_str = str(x)
     parsed_str = str(parsed)
-    assert x_str == parsed_str
+    assert(x_str == parsed_str)
 
 
 # -----------------------------------------------------------------------------
 def test_UUID():
     u = UUID.from_16_bits(0x7788)
-    assert str(u) == 'UUID-16:7788'
+    assert(str(u) == 'UUID-16:7788')
     u = UUID.from_32_bits(0x11223344)
-    assert str(u) == 'UUID-32:11223344'
+    assert(str(u) == 'UUID-32:11223344')
     u = UUID('61A3512C-09BE-4DDC-A6A6-0B03667AAFC6')
-    assert str(u) == '61A3512C-09BE-4DDC-A6A6-0B03667AAFC6'
+    assert(str(u) == '61A3512C-09BE-4DDC-A6A6-0B03667AAFC6')
     v = UUID(str(u))
-    assert str(v) == '61A3512C-09BE-4DDC-A6A6-0B03667AAFC6'
+    assert(str(v) == '61A3512C-09BE-4DDC-A6A6-0B03667AAFC6')
     w = UUID.from_bytes(v.to_bytes())
-    assert str(w) == '61A3512C-09BE-4DDC-A6A6-0B03667AAFC6'
+    assert(str(w) == '61A3512C-09BE-4DDC-A6A6-0B03667AAFC6')
 
     u1 = UUID.from_16_bits(0x1234)
     b1 = u1.to_bytes(force_128 = True)
     u2 = UUID.from_bytes(b1)
-    assert u1 == u2
+    assert(u1 == u2)
 
     u3 = UUID.from_16_bits(0x180a)
-    assert str(u3) == 'UUID-16:180A (Device Information)'
+    assert(str(u3) == 'UUID-16:180A (Device Information)')
 
 
 # -----------------------------------------------------------------------------
@@ -99,122 +98,6 @@ def test_ATT_Read_By_Group_Type_Request():
     basic_check(pdu)
 
 
-# -----------------------------------------------------------------------------
-@pytest.mark.asyncio
-async def test_characteristic_encoding():
-    class Foo(Characteristic):
-        def encode_value(self, value):
-            return bytes([value])
-
-        def decode_value(self, value_bytes):
-            return value_bytes[0]
-
-    c = Foo(GATT_BATTERY_LEVEL_CHARACTERISTIC, Characteristic.READ, Characteristic.READABLE, 123)
-    x = c.read_value(None)
-    assert x == bytes([123])
-    c.write_value(None, bytes([122]))
-    assert c.value == 122
-
-    class FooProxy(CharacteristicProxy):
-        def __init__(self, characteristic):
-            super().__init__(
-                characteristic.client,
-                characteristic.handle,
-                characteristic.end_group_handle,
-                characteristic.uuid,
-                characteristic.properties
-            )
-
-        def encode_value(self, value):
-            return bytes([value])
-
-        def decode_value(self, value_bytes):
-            return value_bytes[0]
-
-    [client, server] = TwoDevices().devices
-
-    characteristic = Characteristic(
-        'FDB159DB-036C-49E3-B3DB-6325AC750806',
-        Characteristic.READ | Characteristic.WRITE | Characteristic.NOTIFY,
-        Characteristic.READABLE | Characteristic.WRITEABLE,
-        bytes([123])
-    )
-
-    service = Service(
-        '3A657F47-D34F-46B3-B1EC-698E29B6B829',
-        [characteristic]
-    )
-    server.add_service(service)
-
-    await client.power_on()
-    await server.power_on()
-    connection = await client.connect(server.random_address)
-    peer = Peer(connection)
-
-    await peer.discover_services()
-    await peer.discover_characteristics()
-    c = peer.get_characteristics_by_uuid(characteristic.uuid)
-    assert len(c) == 1
-    c = c[0]
-    cp = FooProxy(c)
-
-    v = await cp.read_value()
-    assert v == 123
-    await cp.write_value(124)
-    await async_barrier()
-    assert characteristic.value == bytes([124])
-
-    last_change = None
-
-    def on_change(value):
-        nonlocal last_change
-        last_change = value
-
-    await c.subscribe(on_change)
-    await server.notify_subscribers(characteristic)
-    await async_barrier()
-    assert last_change == characteristic.value
-    last_change = None
-
-    await server.notify_subscribers(characteristic, value=bytes([125]))
-    await async_barrier()
-    assert last_change == bytes([125])
-    last_change = None
-
-    await c.unsubscribe(on_change)
-    await server.notify_subscribers(characteristic)
-    await async_barrier()
-    assert last_change is None
-
-    await cp.subscribe(on_change)
-    await server.notify_subscribers(characteristic)
-    await async_barrier()
-    assert last_change == characteristic.value[0]
-    last_change = None
-
-    await server.notify_subscribers(characteristic, value=bytes([126]))
-    await async_barrier()
-    assert last_change == 126
-    last_change = None
-
-    await cp.unsubscribe(on_change)
-    await server.notify_subscribers(characteristic)
-    await async_barrier()
-    assert last_change is None
-
-    cd = DelegatedCharacteristicAdapter(c, decode=lambda x: x[0])
-    await cd.subscribe(on_change)
-    await server.notify_subscribers(characteristic)
-    await async_barrier()
-    assert last_change == characteristic.value[0]
-    last_change = None
-
-    await cd.unsubscribe(on_change)
-    await server.notify_subscribers(characteristic)
-    await async_barrier()
-    assert last_change is None
-
-
 # -----------------------------------------------------------------------------
 def test_CharacteristicAdapter():
     # Check that the CharacteristicAdapter base class is transparent
@@ -223,21 +106,21 @@ def test_CharacteristicAdapter():
     a = CharacteristicAdapter(c)
 
     value = a.read_value(None)
-    assert value == v
+    assert(value == v)
 
     v = bytes([3, 4, 5])
     a.write_value(None, v)
-    assert c.value == v
+    assert(c.value == v)
 
     # Simple delegated adapter
     a = DelegatedCharacteristicAdapter(c, lambda x: bytes(reversed(x)), lambda x: bytes(reversed(x)))
 
     value = a.read_value(None)
-    assert value == bytes(reversed(v))
+    assert(value == bytes(reversed(v)))
 
     v = bytes([3, 4, 5])
     a.write_value(None, v)
-    assert a.value == bytes(reversed(v))
+    assert(a.value == bytes(reversed(v)))
 
     # Packed adapter with single element format
     v = 1234
@@ -246,10 +129,10 @@ def test_CharacteristicAdapter():
     a = PackedCharacteristicAdapter(c, '>H')
 
     value = a.read_value(None)
-    assert value == pv
+    assert(value == pv)
     c.value = None
     a.write_value(None, pv)
-    assert a.value == v
+    assert(a.value == v)
 
     # Packed adapter with multi-element format
     v1 = 1234
@@ -259,10 +142,10 @@ def test_CharacteristicAdapter():
     a = PackedCharacteristicAdapter(c, '>HH')
 
     value = a.read_value(None)
-    assert value == pv
+    assert(value == pv)
     c.value = None
     a.write_value(None, pv)
-    assert a.value == (v1, v2)
+    assert(a.value == (v1, v2))
 
     # Mapped adapter
     v1 = 1234
@@ -273,10 +156,10 @@ def test_CharacteristicAdapter():
     a = MappedCharacteristicAdapter(c, '>HH', ('v1', 'v2'))
 
     value = a.read_value(None)
-    assert value == pv
+    assert(value == pv)
     c.value = None
     a.write_value(None, pv)
-    assert a.value == mapped
+    assert(a.value == mapped)
 
     # UTF-8 adapter
     v = 'Hello π'
@@ -285,10 +168,10 @@ def test_CharacteristicAdapter():
     a = UTF8CharacteristicAdapter(c)
 
     value = a.read_value(None)
-    assert value == ev
+    assert(value == ev)
     c.value = None
     a.write_value(None, ev)
-    assert a.value == v
+    assert(a.value == v)
 
 
 # -----------------------------------------------------------------------------
@@ -296,13 +179,13 @@ def test_CharacteristicValue():
     b = bytes([1, 2, 3])
     c = CharacteristicValue(read=lambda _: b)
     x = c.read(None)
-    assert x == b
+    assert(x == b)
 
     result = []
     c = CharacteristicValue(write=lambda connection, value: result.append((connection, value)))
     z = object()
     c.write(z, b)
-    assert result == [(z, b)]
+    assert(result == [(z, b)])
 
 
 # -----------------------------------------------------------------------------
@@ -382,35 +265,35 @@ async def test_read_write():
     await peer.discover_services()
     await peer.discover_characteristics()
     c = peer.get_characteristics_by_uuid(characteristic1.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     c1 = c[0]
     c = peer.get_characteristics_by_uuid(characteristic2.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     c2 = c[0]
 
     v1 = await peer.read_value(c1)
-    assert v1 == b''
+    assert(v1 == b'')
     b = bytes([1, 2, 3])
     await peer.write_value(c1, b)
     await async_barrier()
-    assert characteristic1.value == b
+    assert(characteristic1.value == b)
     v1 = await peer.read_value(c1)
-    assert v1 == b
-    assert type(characteristic1._last_value is tuple)
-    assert len(characteristic1._last_value) == 2
-    assert str(characteristic1._last_value[0].peer_address) == str(client.random_address)
-    assert characteristic1._last_value[1] == b
+    assert(v1 == b)
+    assert(type(characteristic1._last_value) is tuple)
+    assert(len(characteristic1._last_value) == 2)
+    assert(str(characteristic1._last_value[0].peer_address) == str(client.random_address))
+    assert(characteristic1._last_value[1] == b)
     bb = bytes([3, 4, 5, 6])
     characteristic1.value = bb
     v1 = await peer.read_value(c1)
-    assert v1 == bb
+    assert(v1 == bb)
 
     await peer.write_value(c2, b)
     await async_barrier()
-    assert type(characteristic2._last_value is tuple)
-    assert len(characteristic2._last_value) == 2
-    assert str(characteristic2._last_value[0].peer_address) == str(client.random_address)
-    assert characteristic2._last_value[1] == b
+    assert(type(characteristic2._last_value) is tuple)
+    assert(len(characteristic2._last_value) == 2)
+    assert(str(characteristic2._last_value[0].peer_address) == str(client.random_address))
+    assert(characteristic2._last_value[1] == b)
 
 
 # -----------------------------------------------------------------------------
@@ -441,26 +324,26 @@ async def test_read_write2():
 
     await peer.discover_services()
     c = peer.get_services_by_uuid(service1.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     s = c[0]
     await s.discover_characteristics()
     c = s.get_characteristics_by_uuid(characteristic1.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     c1 = c[0]
 
     v1 = await c1.read_value()
-    assert v1 == v
+    assert(v1 == v)
 
     a1 = PackedCharacteristicAdapter(c1, '>I')
     v1 = await a1.read_value()
-    assert v1 == struct.unpack('>I', v)[0]
+    assert(v1 == struct.unpack('>I', v)[0])
 
     b = bytes([0x55, 0x66, 0x77, 0x88])
     await a1.write_value(struct.unpack('>I', b)[0])
     await async_barrier()
-    assert characteristic1.value == b
+    assert(characteristic1.value == b)
     v1 = await a1.read_value()
-    assert v1 == struct.unpack('>I', b)[0]
+    assert(v1 == struct.unpack('>I', b)[0])
 
 
 # -----------------------------------------------------------------------------
@@ -527,13 +410,13 @@ async def test_subscribe_notify():
     await peer.discover_services()
     await peer.discover_characteristics()
     c = peer.get_characteristics_by_uuid(characteristic1.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     c1 = c[0]
     c = peer.get_characteristics_by_uuid(characteristic2.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     c2 = c[0]
     c = peer.get_characteristics_by_uuid(characteristic3.uuid)
-    assert len(c) == 1
+    assert(len(c) == 1)
     c3 = c[0]
 
     c1._called = False
@@ -546,32 +429,23 @@ async def test_subscribe_notify():
     c1.on('update', on_c1_update)
     await peer.subscribe(c1)
     await async_barrier()
-    assert server._last_subscription[1] == characteristic1
-    assert server._last_subscription[2]
-    assert not server._last_subscription[3]
-    assert characteristic1._last_subscription[1]
-    assert not characteristic1._last_subscription[2]
+    assert(server._last_subscription[1] == characteristic1)
+    assert(server._last_subscription[2])
+    assert(not server._last_subscription[3])
+    assert(characteristic1._last_subscription[1])
+    assert(not characteristic1._last_subscription[2])
     await server.indicate_subscribers(characteristic1)
     await async_barrier()
-    assert not c1._called
+    assert(not c1._called)
     await server.notify_subscribers(characteristic1)
     await async_barrier()
-    assert c1._called
-    assert c1._last_update == characteristic1.value
-
-    c1._called = False
-    c1._last_update = None
-    c1_value = characteristic1.value
-    await server.notify_subscribers(characteristic1, bytes([0, 1, 2]))
-    await async_barrier()
-    assert c1._called
-    assert c1._last_update == bytes([0, 1, 2])
-    assert characteristic1.value == c1_value
+    assert(c1._called)
+    assert(c1._last_update == characteristic1.value)
 
     c1._called = False
     await peer.unsubscribe(c1)
     await server.notify_subscribers(characteristic1)
-    assert not c1._called
+    assert(not c1._called)
 
     c2._called = False
     c2._last_update = None
@@ -584,17 +458,17 @@ async def test_subscribe_notify():
     await async_barrier()
     await server.notify_subscriber(characteristic2._last_subscription[0], characteristic2)
     await async_barrier()
-    assert not c2._called
+    assert(not c2._called)
     await server.indicate_subscriber(characteristic2._last_subscription[0], characteristic2)
     await async_barrier()
-    assert c2._called
-    assert c2._last_update == characteristic2.value
+    assert(c2._called)
+    assert(c2._last_update == characteristic2.value)
 
     c2._called = False
     await peer.unsubscribe(c2, on_c2_update)
     await server.indicate_subscriber(characteristic2._last_subscription[0], characteristic2)
     await async_barrier()
-    assert not c2._called
+    assert(not c2._called)
 
     def on_c3_update(value):
         c3._called = True
@@ -609,17 +483,17 @@ async def test_subscribe_notify():
     await async_barrier()
     await server.notify_subscriber(characteristic3._last_subscription[0], characteristic3)
     await async_barrier()
-    assert c3._called
-    assert c3._last_update == characteristic3.value
-    assert c3._called_2
-    assert c3._last_update_2 == characteristic3.value
+    assert(c3._called)
+    assert(c3._last_update == characteristic3.value)
+    assert(c3._called_2)
+    assert(c3._last_update_2 == characteristic3.value)
     characteristic3.value = bytes([1, 2, 3])
     await server.indicate_subscriber(characteristic3._last_subscription[0], characteristic3)
     await async_barrier()
-    assert c3._called
-    assert c3._last_update == characteristic3.value
-    assert c3._called_2
-    assert c3._last_update_2 == characteristic3.value
+    assert(c3._called)
+    assert(c3._last_update == characteristic3.value)
+    assert(c3._called_2)
+    assert(c3._last_update_2 == characteristic3.value)
 
     c3._called = False
     c3._called_2 = False
@@ -627,8 +501,8 @@ async def test_subscribe_notify():
     await server.notify_subscriber(characteristic3._last_subscription[0], characteristic3)
     await server.indicate_subscriber(characteristic3._last_subscription[0], characteristic3)
     await async_barrier()
-    assert not c3._called
-    assert not c3._called_2
+    assert(not c3._called)
+    assert(not c3._called_2)
 
 
 # -----------------------------------------------------------------------------
@@ -636,8 +510,6 @@ async def async_main():
     await test_read_write()
     await test_read_write2()
     await test_subscribe_notify()
-    await test_characteristic_encoding()
-
 
 # -----------------------------------------------------------------------------
 if __name__ == '__main__':