tests: replace pycodestyle with black
[vpp.git] / test / test_bfd.py
index d1c7b92..c7ea79a 100644 (file)
@@ -21,8 +21,15 @@ from scapy.layers.l2 import Ether, GRE
 from scapy.packet import Raw
 
 from config import config
-from bfd import VppBFDAuthKey, BFD, BFDAuthType, VppBFDUDPSession, \
-    BFDDiagCode, BFDState, BFD_vpp_echo
+from bfd import (
+    VppBFDAuthKey,
+    BFD,
+    BFDAuthType,
+    VppBFDUDPSession,
+    BFDDiagCode,
+    BFDState,
+    BFD_vpp_echo,
+)
 from framework import tag_fixme_vpp_workers
 from framework import VppTestCase, VppTestRunner
 from framework import tag_run_solo
@@ -30,8 +37,7 @@ from util import ppp
 from vpp_ip import DpoProto
 from vpp_ip_route import VppIpRoute, VppRoutePath
 from vpp_lo_interface import VppLoInterface
-from vpp_papi_provider import UnexpectedApiReturnValueError, \
-    CliFailedCommandError
+from vpp_papi_provider import UnexpectedApiReturnValueError, CliFailedCommandError
 from vpp_pg_interface import CaptureTimeoutError, is_ipv6_misc
 from vpp_gre_interface import VppGreInterface
 from vpp_papi import VppEnum
@@ -46,15 +52,17 @@ class AuthKeyFactory(object):
         self._conf_key_ids = {}
 
     def create_random_key(self, test, auth_type=BFDAuthType.keyed_sha1):
-        """ create a random key with unique conf key id """
+        """create a random key with unique conf key id"""
         conf_key_id = randint(0, 0xFFFFFFFF)
         while conf_key_id in self._conf_key_ids:
             conf_key_id = randint(0, 0xFFFFFFFF)
         self._conf_key_ids[conf_key_id] = 1
         key = scapy.compat.raw(
-            bytearray([randint(0, 255) for _ in range(randint(1, 20))]))
-        return VppBFDAuthKey(test=test, auth_type=auth_type,
-                             conf_key_id=conf_key_id, key=key)
+            bytearray([randint(0, 255) for _ in range(randint(1, 20))])
+        )
+        return VppBFDAuthKey(
+            test=test, auth_type=auth_type, conf_key_id=conf_key_id, key=key
+        )
 
 
 class BFDAPITestCase(VppTestCase):
@@ -87,7 +95,7 @@ class BFDAPITestCase(VppTestCase):
         self.factory = AuthKeyFactory()
 
     def test_add_bfd(self):
-        """ create a BFD session """
+        """create a BFD session"""
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         session.add_vpp_config()
         self.logger.debug("Session state is %s", session.state)
@@ -97,7 +105,7 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_double_add(self):
-        """ create the same BFD session twice (negative case) """
+        """create the same BFD session twice (negative case)"""
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         session.add_vpp_config()
 
@@ -107,9 +115,8 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_add_bfd6(self):
-        """ create IPv6 BFD session """
-        session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
+        """create IPv6 BFD session"""
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
         session.add_vpp_config()
         self.logger.debug("Session state is %s", session.state)
         session.remove_vpp_config()
@@ -118,65 +125,76 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_mod_bfd(self):
-        """ modify BFD session parameters """
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   desired_min_tx=50000,
-                                   required_min_rx=10000,
-                                   detect_mult=1)
+        """modify BFD session parameters"""
+        session = VppBFDUDPSession(
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            desired_min_tx=50000,
+            required_min_rx=10000,
+            detect_mult=1,
+        )
         session.add_vpp_config()
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
-        session.modify_parameters(desired_min_tx=session.desired_min_tx * 2,
-                                  required_min_rx=session.required_min_rx * 2,
-                                  detect_mult=session.detect_mult * 2)
+        session.modify_parameters(
+            desired_min_tx=session.desired_min_tx * 2,
+            required_min_rx=session.required_min_rx * 2,
+            detect_mult=session.detect_mult * 2,
+        )
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
 
     def test_upd_bfd(self):
-        """ Create/Modify w/ Update BFD session parameters """
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   desired_min_tx=50000,
-                                   required_min_rx=10000,
-                                   detect_mult=1)
+        """Create/Modify w/ Update BFD session parameters"""
+        session = VppBFDUDPSession(
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            desired_min_tx=50000,
+            required_min_rx=10000,
+            detect_mult=1,
+        )
         session.upd_vpp_config()
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
 
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
-        session.upd_vpp_config(desired_min_tx=session.desired_min_tx * 2,
-                               required_min_rx=session.required_min_rx * 2,
-                               detect_mult=session.detect_mult * 2)
+        session.upd_vpp_config(
+            desired_min_tx=session.desired_min_tx * 2,
+            required_min_rx=session.required_min_rx * 2,
+            detect_mult=session.detect_mult * 2,
+        )
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
 
     def test_add_sha1_keys(self):
-        """ add SHA1 keys """
+        """add SHA1 keys"""
         key_count = 10
-        keys = [self.factory.create_random_key(
-            self) for i in range(0, key_count)]
+        keys = [self.factory.create_random_key(self) for i in range(0, key_count)]
         for key in keys:
             self.assertFalse(key.query_vpp_config())
         for key in keys:
@@ -211,11 +229,10 @@ class BFDAPITestCase(VppTestCase):
             self.assertFalse(key.query_vpp_config())
 
     def test_add_bfd_sha1(self):
-        """ create a BFD session (SHA1) """
+        """create a BFD session (SHA1)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   sha1_key=key)
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
         session.add_vpp_config()
         self.logger.debug("Session state is %s", session.state)
         session.remove_vpp_config()
@@ -224,51 +241,56 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_double_add_sha1(self):
-        """ create the same BFD session twice (negative case) (SHA1) """
+        """create the same BFD session twice (negative case) (SHA1)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   sha1_key=key)
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
         session.add_vpp_config()
         with self.assertRaises(Exception):
             session.add_vpp_config()
 
     def test_add_auth_nonexistent_key(self):
-        """ create BFD session using non-existent SHA1 (negative case) """
+        """create BFD session using non-existent SHA1 (negative case)"""
         session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4,
-            sha1_key=self.factory.create_random_key(self))
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            sha1_key=self.factory.create_random_key(self),
+        )
         with self.assertRaises(Exception):
             session.add_vpp_config()
 
     def test_shared_sha1_key(self):
-        """ single SHA1 key shared by multiple BFD sessions """
+        """single SHA1 key shared by multiple BFD sessions"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         sessions = [
-            VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                             sha1_key=key),
-            VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6,
-                             sha1_key=key, af=AF_INET6),
-            VppBFDUDPSession(self, self.pg1, self.pg1.remote_ip4,
-                             sha1_key=key),
-            VppBFDUDPSession(self, self.pg1, self.pg1.remote_ip6,
-                             sha1_key=key, af=AF_INET6)]
+            VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key),
+            VppBFDUDPSession(
+                self, self.pg0, self.pg0.remote_ip6, sha1_key=key, af=AF_INET6
+            ),
+            VppBFDUDPSession(self, self.pg1, self.pg1.remote_ip4, sha1_key=key),
+            VppBFDUDPSession(
+                self, self.pg1, self.pg1.remote_ip6, sha1_key=key, af=AF_INET6
+            ),
+        ]
         for s in sessions:
             s.add_vpp_config()
         removed = 0
         for s in sessions:
             e = key.get_bfd_auth_keys_dump_entry()
-            self.assert_equal(e.use_count, len(sessions) - removed,
-                              "Use count for shared key")
+            self.assert_equal(
+                e.use_count, len(sessions) - removed, "Use count for shared key"
+            )
             s.remove_vpp_config()
             removed += 1
         e = key.get_bfd_auth_keys_dump_entry()
-        self.assert_equal(e.use_count, len(sessions) - removed,
-                          "Use count for shared key")
+        self.assert_equal(
+            e.use_count, len(sessions) - removed, "Use count for shared key"
+        )
 
     def test_activate_auth(self):
-        """ activate SHA1 authentication """
+        """activate SHA1 authentication"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
@@ -276,7 +298,7 @@ class BFDAPITestCase(VppTestCase):
         session.activate_auth(key)
 
     def test_deactivate_auth(self):
-        """ deactivate SHA1 authentication """
+        """deactivate SHA1 authentication"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
@@ -285,20 +307,19 @@ class BFDAPITestCase(VppTestCase):
         session.deactivate_auth()
 
     def test_change_key(self):
-        """ change SHA1 key """
+        """change SHA1 key"""
         key1 = self.factory.create_random_key(self)
         key2 = self.factory.create_random_key(self)
         while key2.conf_key_id == key1.conf_key_id:
             key2 = self.factory.create_random_key(self)
         key1.add_vpp_config()
         key2.add_vpp_config()
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   sha1_key=key1)
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key1)
         session.add_vpp_config()
         session.activate_auth(key2)
 
     def test_set_del_udp_echo_source(self):
-        """ set/del udp echo source """
+        """set/del udp echo source"""
         self.create_loopback_interfaces(1)
         self.loopback0 = self.lo_interfaces[0]
         self.loopback0.admin_up()
@@ -307,8 +328,7 @@ class BFDAPITestCase(VppTestCase):
         self.assertFalse(echo_source.have_usable_ip4)
         self.assertFalse(echo_source.have_usable_ip6)
 
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         echo_source = self.vapi.bfd_udp_get_echo_source()
         self.assertTrue(echo_source.is_set)
         self.assertEqual(echo_source.sw_if_index, self.loopback0.sw_if_index)
@@ -316,8 +336,9 @@ class BFDAPITestCase(VppTestCase):
         self.assertFalse(echo_source.have_usable_ip6)
 
         self.loopback0.config_ip4()
-        echo_ip4 = ipaddress.IPv4Address(int(ipaddress.IPv4Address(
-            self.loopback0.local_ip4)) ^ 1).packed
+        echo_ip4 = ipaddress.IPv4Address(
+            int(ipaddress.IPv4Address(self.loopback0.local_ip4)) ^ 1
+        ).packed
         echo_source = self.vapi.bfd_udp_get_echo_source()
         self.assertTrue(echo_source.is_set)
         self.assertEqual(echo_source.sw_if_index, self.loopback0.sw_if_index)
@@ -326,8 +347,9 @@ class BFDAPITestCase(VppTestCase):
         self.assertFalse(echo_source.have_usable_ip6)
 
         self.loopback0.config_ip6()
-        echo_ip6 = ipaddress.IPv6Address(int(ipaddress.IPv6Address(
-            self.loopback0.local_ip6)) ^ 1).packed
+        echo_ip6 = ipaddress.IPv6Address(
+            int(ipaddress.IPv6Address(self.loopback0.local_ip6)) ^ 1
+        ).packed
 
         echo_source = self.vapi.bfd_udp_get_echo_source()
         self.assertTrue(echo_source.is_set)
@@ -345,11 +367,20 @@ class BFDAPITestCase(VppTestCase):
 
 
 class BFDTestSession(object):
-    """ BFD session as seen from test framework side """
-
-    def __init__(self, test, interface, af, detect_mult=3, sha1_key=None,
-                 bfd_key_id=None, our_seq_number=None,
-                 tunnel_header=None, phy_interface=None):
+    """BFD session as seen from test framework side"""
+
+    def __init__(
+        self,
+        test,
+        interface,
+        af,
+        detect_mult=3,
+        sha1_key=None,
+        bfd_key_id=None,
+        our_seq_number=None,
+        tunnel_header=None,
+        phy_interface=None,
+    ):
         self.test = test
         self.af = af
         self.sha1_key = sha1_key
@@ -381,17 +412,25 @@ class BFDTestSession(object):
         self.rx_packets_echo = 0
 
     def inc_seq_num(self):
-        """ increment sequence number, wrapping if needed """
+        """increment sequence number, wrapping if needed"""
         if self.our_seq_number == 0xFFFFFFFF:
             self.our_seq_number = 0
         else:
             self.our_seq_number += 1
 
-    def update(self, my_discriminator=None, your_discriminator=None,
-               desired_min_tx=None, required_min_rx=None,
-               required_min_echo_rx=None, detect_mult=None,
-               diag=None, state=None, auth_type=None):
-        """ update BFD parameters associated with session """
+    def update(
+        self,
+        my_discriminator=None,
+        your_discriminator=None,
+        desired_min_tx=None,
+        required_min_rx=None,
+        required_min_echo_rx=None,
+        detect_mult=None,
+        diag=None,
+        state=None,
+        auth_type=None,
+    ):
+        """update BFD parameters associated with session"""
         if my_discriminator is not None:
             self.my_discriminator = my_discriminator
         if your_discriminator is not None:
@@ -412,34 +451,37 @@ class BFDTestSession(object):
             self.auth_type = auth_type
 
     def fill_packet_fields(self, packet):
-        """ set packet fields with known values in packet """
+        """set packet fields with known values in packet"""
         bfd = packet[BFD]
         if self.my_discriminator:
-            self.test.logger.debug("BFD: setting packet.my_discriminator=%s",
-                                   self.my_discriminator)
+            self.test.logger.debug(
+                "BFD: setting packet.my_discriminator=%s", self.my_discriminator
+            )
             bfd.my_discriminator = self.my_discriminator
         if self.your_discriminator:
-            self.test.logger.debug("BFD: setting packet.your_discriminator=%s",
-                                   self.your_discriminator)
+            self.test.logger.debug(
+                "BFD: setting packet.your_discriminator=%s", self.your_discriminator
+            )
             bfd.your_discriminator = self.your_discriminator
         if self.required_min_rx:
             self.test.logger.debug(
-                "BFD: setting packet.required_min_rx_interval=%s",
-                self.required_min_rx)
+                "BFD: setting packet.required_min_rx_interval=%s", self.required_min_rx
+            )
             bfd.required_min_rx_interval = self.required_min_rx
         if self.required_min_echo_rx:
             self.test.logger.debug(
-                "BFD: setting packet.required_min_echo_rx=%s",
-                self.required_min_echo_rx)
+                "BFD: setting packet.required_min_echo_rx=%s", self.required_min_echo_rx
+            )
             bfd.required_min_echo_rx_interval = self.required_min_echo_rx
         if self.desired_min_tx:
             self.test.logger.debug(
-                "BFD: setting packet.desired_min_tx_interval=%s",
-                self.desired_min_tx)
+                "BFD: setting packet.desired_min_tx_interval=%s", self.desired_min_tx
+            )
             bfd.desired_min_tx_interval = self.desired_min_tx
         if self.detect_mult:
             self.test.logger.debug(
-                "BFD: setting packet.detect_mult=%s", self.detect_mult)
+                "BFD: setting packet.detect_mult=%s", self.detect_mult
+            )
             bfd.detect_mult = self.detect_mult
         if self.diag:
             self.test.logger.debug("BFD: setting packet.diag=%s", self.diag)
@@ -449,12 +491,11 @@ class BFDTestSession(object):
             bfd.state = self.state
         if self.auth_type:
             # this is used by a negative test-case
-            self.test.logger.debug("BFD: setting packet.auth_type=%s",
-                                   self.auth_type)
+            self.test.logger.debug("BFD: setting packet.auth_type=%s", self.auth_type)
             bfd.auth_type = self.auth_type
 
     def create_packet(self):
-        """ create a BFD packet, reflecting the current state of session """
+        """create a BFD packet, reflecting the current state of session"""
         if self.sha1_key:
             bfd = BFD(flags="A")
             bfd.auth_type = self.sha1_key.auth_type
@@ -464,37 +505,48 @@ class BFDTestSession(object):
             bfd.length = BFD.sha1_auth_len + BFD.bfd_pkt_len
         else:
             bfd = BFD()
-        packet = Ether(src=self.phy_interface.remote_mac,
-                       dst=self.phy_interface.local_mac)
+        packet = Ether(
+            src=self.phy_interface.remote_mac, dst=self.phy_interface.local_mac
+        )
         if self.tunnel_header:
             packet = packet / self.tunnel_header
         if self.af == AF_INET6:
-            packet = (packet /
-                      IPv6(src=self.interface.remote_ip6,
-                           dst=self.interface.local_ip6,
-                           hlim=255) /
-                      UDP(sport=self.udp_sport, dport=BFD.udp_dport) /
-                      bfd)
+            packet = (
+                packet
+                / IPv6(
+                    src=self.interface.remote_ip6,
+                    dst=self.interface.local_ip6,
+                    hlim=255,
+                )
+                / UDP(sport=self.udp_sport, dport=BFD.udp_dport)
+                / bfd
+            )
         else:
-            packet = (packet /
-                      IP(src=self.interface.remote_ip4,
-                         dst=self.interface.local_ip4,
-                         ttl=255) /
-                      UDP(sport=self.udp_sport, dport=BFD.udp_dport) /
-                      bfd)
+            packet = (
+                packet
+                / IP(
+                    src=self.interface.remote_ip4, dst=self.interface.local_ip4, ttl=255
+                )
+                / UDP(sport=self.udp_sport, dport=BFD.udp_dport)
+                / bfd
+            )
         self.test.logger.debug("BFD: Creating packet")
         self.fill_packet_fields(packet)
         if self.sha1_key:
-            hash_material = scapy.compat.raw(
-                packet[BFD])[:32] + self.sha1_key.key + \
-                b"\0" * (20 - len(self.sha1_key.key))
-            self.test.logger.debug("BFD: Calculated SHA1 hash: %s" %
-                                   hashlib.sha1(hash_material).hexdigest())
+            hash_material = (
+                scapy.compat.raw(packet[BFD])[:32]
+                + self.sha1_key.key
+                + b"\0" * (20 - len(self.sha1_key.key))
+            )
+            self.test.logger.debug(
+                "BFD: Calculated SHA1 hash: %s"
+                % hashlib.sha1(hash_material).hexdigest()
+            )
             packet[BFD].auth_key_hash = hashlib.sha1(hash_material).digest()
         return packet
 
     def send_packet(self, packet=None, interface=None):
-        """ send packet on interface, creating the packet if needed """
+        """send packet on interface, creating the packet if needed"""
         if packet is None:
             packet = self.create_packet()
         if interface is None:
@@ -505,82 +557,95 @@ class BFDTestSession(object):
         self.test.pg_start()
 
     def verify_sha1_auth(self, packet):
-        """ Verify correctness of authentication in BFD layer. """
+        """Verify correctness of authentication in BFD layer."""
         bfd = packet[BFD]
         self.test.assert_equal(bfd.auth_len, 28, "Auth section length")
-        self.test.assert_equal(bfd.auth_type, self.sha1_key.auth_type,
-                               BFDAuthType)
+        self.test.assert_equal(bfd.auth_type, self.sha1_key.auth_type, BFDAuthType)
         self.test.assert_equal(bfd.auth_key_id, self.bfd_key_id, "Key ID")
         self.test.assert_equal(bfd.auth_reserved, 0, "Reserved")
         if self.vpp_seq_number is None:
             self.vpp_seq_number = bfd.auth_seq_num
-            self.test.logger.debug("Received initial sequence number: %s" %
-                                   self.vpp_seq_number)
+            self.test.logger.debug(
+                "Received initial sequence number: %s" % self.vpp_seq_number
+            )
         else:
             recvd_seq_num = bfd.auth_seq_num
-            self.test.logger.debug("Received followup sequence number: %s" %
-                                   recvd_seq_num)
-            if self.vpp_seq_number < 0xffffffff:
-                if self.sha1_key.auth_type == \
-                        BFDAuthType.meticulous_keyed_sha1:
-                    self.test.assert_equal(recvd_seq_num,
-                                           self.vpp_seq_number + 1,
-                                           "BFD sequence number")
+            self.test.logger.debug(
+                "Received followup sequence number: %s" % recvd_seq_num
+            )
+            if self.vpp_seq_number < 0xFFFFFFFF:
+                if self.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1:
+                    self.test.assert_equal(
+                        recvd_seq_num, self.vpp_seq_number + 1, "BFD sequence number"
+                    )
                 else:
-                    self.test.assert_in_range(recvd_seq_num,
-                                              self.vpp_seq_number,
-                                              self.vpp_seq_number + 1,
-                                              "BFD sequence number")
+                    self.test.assert_in_range(
+                        recvd_seq_num,
+                        self.vpp_seq_number,
+                        self.vpp_seq_number + 1,
+                        "BFD sequence number",
+                    )
             else:
-                if self.sha1_key.auth_type == \
-                        BFDAuthType.meticulous_keyed_sha1:
-                    self.test.assert_equal(recvd_seq_num, 0,
-                                           "BFD sequence number")
+                if self.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1:
+                    self.test.assert_equal(recvd_seq_num, 0, "BFD sequence number")
                 else:
-                    self.test.assertIn(recvd_seq_num, (self.vpp_seq_number, 0),
-                                       "BFD sequence number not one of "
-                                       "(%s, 0)" % self.vpp_seq_number)
+                    self.test.assertIn(
+                        recvd_seq_num,
+                        (self.vpp_seq_number, 0),
+                        "BFD sequence number not one of "
+                        "(%s, 0)" % self.vpp_seq_number,
+                    )
             self.vpp_seq_number = recvd_seq_num
         # last 20 bytes represent the hash - so replace them with the key,
         # pad the result with zeros and hash the result
-        hash_material = bfd.original[:-20] + self.sha1_key.key + \
-            b"\0" * (20 - len(self.sha1_key.key))
+        hash_material = (
+            bfd.original[:-20]
+            + self.sha1_key.key
+            + b"\0" * (20 - len(self.sha1_key.key))
+        )
         expected_hash = hashlib.sha1(hash_material).hexdigest()
-        self.test.assert_equal(binascii.hexlify(bfd.auth_key_hash),
-                               expected_hash.encode(), "Auth key hash")
+        self.test.assert_equal(
+            binascii.hexlify(bfd.auth_key_hash), expected_hash.encode(), "Auth key hash"
+        )
 
     def verify_bfd(self, packet):
-        """ Verify correctness of BFD layer. """
+        """Verify correctness of BFD layer."""
         bfd = packet[BFD]
         self.test.assert_equal(bfd.version, 1, "BFD version")
-        self.test.assert_equal(bfd.your_discriminator,
-                               self.my_discriminator,
-                               "BFD - your discriminator")
+        self.test.assert_equal(
+            bfd.your_discriminator, self.my_discriminator, "BFD - your discriminator"
+        )
         if self.sha1_key:
             self.verify_sha1_auth(packet)
 
 
 def bfd_session_up(test):
-    """ Bring BFD session up """
+    """Bring BFD session up"""
     test.logger.info("BFD: Waiting for slow hello")
     p = wait_for_bfd_packet(test, 2, is_tunnel=test.vpp_session.is_tunnel)
     old_offset = None
-    if hasattr(test, 'vpp_clock_offset'):
+    if hasattr(test, "vpp_clock_offset"):
         old_offset = test.vpp_clock_offset
     test.vpp_clock_offset = time.time() - float(p.time)
-    test.logger.debug("BFD: Calculated vpp clock offset: %s",
-                      test.vpp_clock_offset)
+    test.logger.debug("BFD: Calculated vpp clock offset: %s", test.vpp_clock_offset)
     if old_offset:
         test.assertAlmostEqual(
-            old_offset, test.vpp_clock_offset, delta=0.5,
-            msg="vpp clock offset not stable (new: %s, old: %s)" %
-            (test.vpp_clock_offset, old_offset))
+            old_offset,
+            test.vpp_clock_offset,
+            delta=0.5,
+            msg="vpp clock offset not stable (new: %s, old: %s)"
+            % (test.vpp_clock_offset, old_offset),
+        )
     test.logger.info("BFD: Sending Init")
-    test.test_session.update(my_discriminator=randint(0, 40000000),
-                             your_discriminator=p[BFD].my_discriminator,
-                             state=BFDState.init)
-    if test.test_session.sha1_key and test.test_session.sha1_key.auth_type == \
-            BFDAuthType.meticulous_keyed_sha1:
+    test.test_session.update(
+        my_discriminator=randint(0, 40000000),
+        your_discriminator=p[BFD].my_discriminator,
+        state=BFDState.init,
+    )
+    if (
+        test.test_session.sha1_key
+        and test.test_session.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1
+    ):
         test.test_session.inc_seq_num()
     test.test_session.send_packet()
     test.logger.info("BFD: Waiting for event")
@@ -588,19 +653,23 @@ def bfd_session_up(test):
     verify_event(test, e, expected_state=BFDState.up)
     test.logger.info("BFD: Session is Up")
     test.test_session.update(state=BFDState.up)
-    if test.test_session.sha1_key and test.test_session.sha1_key.auth_type == \
-            BFDAuthType.meticulous_keyed_sha1:
+    if (
+        test.test_session.sha1_key
+        and test.test_session.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1
+    ):
         test.test_session.inc_seq_num()
     test.test_session.send_packet()
     test.assert_equal(test.vpp_session.state, BFDState.up, BFDState)
 
 
 def bfd_session_down(test):
-    """ Bring BFD session down """
+    """Bring BFD session down"""
     test.assert_equal(test.vpp_session.state, BFDState.up, BFDState)
     test.test_session.update(state=BFDState.down)
-    if test.test_session.sha1_key and test.test_session.sha1_key.auth_type == \
-            BFDAuthType.meticulous_keyed_sha1:
+    if (
+        test.test_session.sha1_key
+        and test.test_session.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1
+    ):
         test.test_session.inc_seq_num()
     test.test_session.send_packet()
     test.logger.info("BFD: Waiting for event")
@@ -617,25 +686,25 @@ def verify_bfd_session_config(test, session, state=None):
     # are valid (in get_bfd_udp_session_dump_entry)
     if state:
         test.assert_equal(dump.state, state, "session state")
-    test.assert_equal(dump.required_min_rx, session.required_min_rx,
-                      "required min rx interval")
-    test.assert_equal(dump.desired_min_tx, session.desired_min_tx,
-                      "desired min tx interval")
-    test.assert_equal(dump.detect_mult, session.detect_mult,
-                      "detect multiplier")
+    test.assert_equal(
+        dump.required_min_rx, session.required_min_rx, "required min rx interval"
+    )
+    test.assert_equal(
+        dump.desired_min_tx, session.desired_min_tx, "desired min tx interval"
+    )
+    test.assert_equal(dump.detect_mult, session.detect_mult, "detect multiplier")
     if session.sha1_key is None:
         test.assert_equal(dump.is_authenticated, 0, "is_authenticated flag")
     else:
         test.assert_equal(dump.is_authenticated, 1, "is_authenticated flag")
-        test.assert_equal(dump.bfd_key_id, session.bfd_key_id,
-                          "bfd key id")
-        test.assert_equal(dump.conf_key_id,
-                          session.sha1_key.conf_key_id,
-                          "config key id")
+        test.assert_equal(dump.bfd_key_id, session.bfd_key_id, "bfd key id")
+        test.assert_equal(
+            dump.conf_key_id, session.sha1_key.conf_key_id, "config key id"
+        )
 
 
 def verify_ip(test, packet):
-    """ Verify correctness of IP layer. """
+    """Verify correctness of IP layer."""
     if test.vpp_session.af == AF_INET6:
         ip = packet[IPv6]
         local_ip = test.vpp_session.interface.local_ip6
@@ -651,30 +720,31 @@ def verify_ip(test, packet):
 
 
 def verify_udp(test, packet):
-    """ Verify correctness of UDP layer. """
+    """Verify correctness of UDP layer."""
     udp = packet[UDP]
     test.assert_equal(udp.dport, BFD.udp_dport, "UDP destination port")
-    test.assert_in_range(udp.sport, BFD.udp_sport_min, BFD.udp_sport_max,
-                         "UDP source port")
+    test.assert_in_range(
+        udp.sport, BFD.udp_sport_min, BFD.udp_sport_max, "UDP source port"
+    )
 
 
 def verify_event(test, event, expected_state):
-    """ Verify correctness of event values. """
+    """Verify correctness of event values."""
     e = event
     test.logger.debug("BFD: Event: %s" % reprlib.repr(e))
-    test.assert_equal(e.sw_if_index,
-                      test.vpp_session.interface.sw_if_index,
-                      "BFD interface index")
-
-    test.assert_equal(str(e.local_addr), test.vpp_session.local_addr,
-                      "Local IPv6 address")
-    test.assert_equal(str(e.peer_addr), test.vpp_session.peer_addr,
-                      "Peer IPv6 address")
+    test.assert_equal(
+        e.sw_if_index, test.vpp_session.interface.sw_if_index, "BFD interface index"
+    )
+
+    test.assert_equal(
+        str(e.local_addr), test.vpp_session.local_addr, "Local IPv6 address"
+    )
+    test.assert_equal(str(e.peer_addr), test.vpp_session.peer_addr, "Peer IPv6 address")
     test.assert_equal(e.state, expected_state, BFDState)
 
 
 def wait_for_bfd_packet(test, timeout=1, pcap_time_min=None, is_tunnel=False):
-    """ wait for BFD packet and verify its correctness
+    """wait for BFD packet and verify its correctness
 
     :param timeout: how long to wait
     :param pcap_time_min: ignore packets with pcap timestamp lower than this
@@ -695,9 +765,13 @@ def wait_for_bfd_packet(test, timeout=1, pcap_time_min=None, is_tunnel=False):
         test.test_session.rx_packets += 1
         test.logger.debug(ppp("BFD: Got packet:", p))
         if pcap_time_min is not None and p.time < pcap_time_min:
-            test.logger.debug(ppp("BFD: ignoring packet (pcap time %s < "
-                                  "pcap time min %s):" %
-                                  (p.time, pcap_time_min), p))
+            test.logger.debug(
+                ppp(
+                    "BFD: ignoring packet (pcap time %s < "
+                    "pcap time min %s):" % (p.time, pcap_time_min),
+                    p,
+                )
+            )
         else:
             break
     if is_tunnel:
@@ -722,15 +796,15 @@ def bfd_grab_stats_snapshot(test, bs_idx=0, thread_index=None):
     s = test.statistics
     ti = thread_index
     if ti is None:
-        rx = s['/bfd/rx-session-counters'][:, bs_idx].sum_packets()
-        rx_echo = s['/bfd/rx-session-echo-counters'][:, bs_idx].sum_packets()
-        tx = s['/bfd/tx-session-counters'][:, bs_idx].sum_packets()
-        tx_echo = s['/bfd/tx-session-echo-counters'][:, bs_idx].sum_packets()
+        rx = s["/bfd/rx-session-counters"][:, bs_idx].sum_packets()
+        rx_echo = s["/bfd/rx-session-echo-counters"][:, bs_idx].sum_packets()
+        tx = s["/bfd/tx-session-counters"][:, bs_idx].sum_packets()
+        tx_echo = s["/bfd/tx-session-echo-counters"][:, bs_idx].sum_packets()
     else:
-        rx = s['/bfd/rx-session-counters'][ti, bs_idx].sum_packets()
-        rx_echo = s['/bfd/rx-session-echo-counters'][ti, bs_idx].sum_packets()
-        tx = s['/bfd/tx-session-counters'][ti, bs_idx].sum_packets()
-        tx_echo = s['/bfd/tx-session-echo-counters'][ti, bs_idx].sum_packets()
+        rx = s["/bfd/rx-session-counters"][ti, bs_idx].sum_packets()
+        rx_echo = s["/bfd/rx-session-echo-counters"][ti, bs_idx].sum_packets()
+        tx = s["/bfd/tx-session-counters"][ti, bs_idx].sum_packets()
+        tx_echo = s["/bfd/tx-session-echo-counters"][ti, bs_idx].sum_packets()
     return BFDStats(rx, rx_echo, tx, tx_echo)
 
 
@@ -780,10 +854,9 @@ class BFD4TestCase(VppTestCase):
         self.vapi.want_bfd_events()
         self.pg0.enable_capture()
         try:
-            self.bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-            self.bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
-            self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                                self.pg0.remote_ip4)
+            self.bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+            self.bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
+            self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
             self.vpp_session.add_vpp_config()
             self.vpp_session.admin_up()
             self.test_session = BFDTestSession(self, self.pg0, AF_INET)
@@ -798,26 +871,29 @@ class BFD4TestCase(VppTestCase):
         super(BFD4TestCase, self).tearDown()
 
     def test_session_up(self):
-        """ bring BFD session up """
+        """bring BFD session up"""
         bfd_session_up(self)
-        bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-        bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
+        bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+        bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
         self.assert_equal(bfd_udp4_sessions - self.bfd_udp4_sessions, 1)
         self.assert_equal(bfd_udp6_sessions, self.bfd_udp6_sessions)
 
     def test_session_up_by_ip(self):
-        """ bring BFD session up - first frame looked up by address pair """
+        """bring BFD session up - first frame looked up by address pair"""
         self.logger.info("BFD: Sending Slow control frame")
         self.test_session.update(my_discriminator=randint(0, 40000000))
         self.test_session.send_packet()
         self.pg0.enable_capture()
         p = self.pg0.wait_for_packet(1)
-        self.assert_equal(p[BFD].your_discriminator,
-                          self.test_session.my_discriminator,
-                          "BFD - your discriminator")
+        self.assert_equal(
+            p[BFD].your_discriminator,
+            self.test_session.my_discriminator,
+            "BFD - your discriminator",
+        )
         self.assert_equal(p[BFD].state, BFDState.init, BFDState)
-        self.test_session.update(your_discriminator=p[BFD].my_discriminator,
-                                 state=BFDState.up)
+        self.test_session.update(
+            your_discriminator=p[BFD].my_discriminator, state=BFDState.up
+        )
         self.logger.info("BFD: Waiting for event")
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.init)
@@ -832,21 +908,20 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_session_down(self):
-        """ bring BFD session down """
+        """bring BFD session down"""
         bfd_session_up(self)
         bfd_session_down(self)
 
     def test_hold_up(self):
-        """ hold BFD session up """
+        """hold BFD session up"""
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             wait_for_bfd_packet(self)
             self.test_session.send_packet()
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_slow_timer(self):
-        """ verify slow periodic control frames while session down """
+        """verify slow periodic control frames while session down"""
         packet_count = 3
         self.logger.info("BFD: Waiting for %d BFD packets", packet_count)
         prev_packet = wait_for_bfd_packet(self, 2)
@@ -855,55 +930,60 @@ class BFD4TestCase(VppTestCase):
             time_diff = next_packet.time - prev_packet.time
             # spec says the range should be <0.75, 1>, allow extra 0.05 margin
             # to work around timing issues
-            self.assert_in_range(
-                time_diff, 0.70, 1.05, "time between slow packets")
+            self.assert_in_range(time_diff, 0.70, 1.05, "time between slow packets")
             prev_packet = next_packet
 
     def test_zero_remote_min_rx(self):
-        """ no packets when zero remote required min rx interval """
+        """no packets when zero remote required min rx interval"""
         bfd_session_up(self)
         self.test_session.update(required_min_rx=0)
         self.test_session.send_packet()
         for dummy in range(self.test_session.detect_mult):
-            self.sleep(self.vpp_session.required_min_rx / USEC_IN_SEC,
-                       "sleep before transmitting bfd packet")
+            self.sleep(
+                self.vpp_session.required_min_rx / USEC_IN_SEC,
+                "sleep before transmitting bfd packet",
+            )
             self.test_session.send_packet()
             try:
                 p = wait_for_bfd_packet(self, timeout=0)
                 self.logger.error(ppp("Received unexpected packet:", p))
             except CaptureTimeoutError:
                 pass
-        self.assert_equal(
-            len(self.vapi.collect_events()), 0, "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
         self.test_session.update(required_min_rx=300000)
         for dummy in range(3):
             self.test_session.send_packet()
             wait_for_bfd_packet(
-                self, timeout=self.test_session.required_min_rx / USEC_IN_SEC)
-        self.assert_equal(
-            len(self.vapi.collect_events()), 0, "number of bfd events")
+                self, timeout=self.test_session.required_min_rx / USEC_IN_SEC
+            )
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_conn_down(self):
-        """ verify session goes down after inactivity """
+        """verify session goes down after inactivity"""
         bfd_session_up(self)
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         self.sleep(detection_time, "waiting for BFD session time-out")
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.down)
 
     def test_peer_discr_reset_sess_down(self):
-        """ peer discriminator reset after session goes down """
+        """peer discriminator reset after session goes down"""
         bfd_session_up(self)
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         self.sleep(detection_time, "waiting for BFD session time-out")
         self.test_session.my_discriminator = 0
-        wait_for_bfd_packet(self,
-                            pcap_time_min=time.time() - self.vpp_clock_offset)
+        wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
 
     def test_large_required_min_rx(self):
-        """ large remote required min rx interval """
+        """large remote required min rx interval"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
         interval = 3000000
@@ -932,14 +1012,14 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(count, 0, "number of packets received")
 
     def test_immediate_remote_min_rx_reduction(self):
-        """ immediately honor remote required min rx reduction """
+        """immediately honor remote required min rx reduction"""
         self.vpp_session.remove_vpp_config()
         self.vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, desired_min_tx=10000)
+            self, self.pg0, self.pg0.remote_ip4, desired_min_tx=10000
+        )
         self.pg0.enable_capture()
         self.vpp_session.add_vpp_config()
-        self.test_session.update(desired_min_tx=1000000,
-                                 required_min_rx=1000000)
+        self.test_session.update(desired_min_tx=1000000, required_min_rx=1000000)
         bfd_session_up(self)
         reference_packet = wait_for_bfd_packet(self)
         time_mark = time.time()
@@ -950,131 +1030,143 @@ class BFD4TestCase(VppTestCase):
         p = wait_for_bfd_packet(self)
         # first packet is allowed to be late by time we spent doing the update
         # calculated in extra_time
-        self.assert_in_range(p.time - reference_packet.time,
-                             .95 * 0.75 * interval / USEC_IN_SEC,
-                             1.05 * interval / USEC_IN_SEC + extra_time,
-                             "time between BFD packets")
+        self.assert_in_range(
+            p.time - reference_packet.time,
+            0.95 * 0.75 * interval / USEC_IN_SEC,
+            1.05 * interval / USEC_IN_SEC + extra_time,
+            "time between BFD packets",
+        )
         reference_packet = p
         for dummy in range(3):
             p = wait_for_bfd_packet(self)
             diff = p.time - reference_packet.time
-            self.assert_in_range(diff, .95 * .75 * interval / USEC_IN_SEC,
-                                 1.05 * interval / USEC_IN_SEC,
-                                 "time between BFD packets")
+            self.assert_in_range(
+                diff,
+                0.95 * 0.75 * interval / USEC_IN_SEC,
+                1.05 * interval / USEC_IN_SEC,
+                "time between BFD packets",
+            )
             reference_packet = p
 
     def test_modify_req_min_rx_double(self):
-        """ modify session - double required min rx """
+        """modify session - double required min rx"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
-        self.test_session.update(desired_min_tx=10000,
-                                 required_min_rx=10000)
+        self.test_session.update(desired_min_tx=10000, required_min_rx=10000)
         self.test_session.send_packet()
         # double required min rx
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         # poll bit needs to be set
-        self.assertIn("P", p.sprintf("%BFD.flags%"),
-                      "Poll bit not set in BFD packet")
+        self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet")
         # finish poll sequence with final packet
         final = self.test_session.create_packet()
         final[BFD].flags = "F"
-        timeout = self.test_session.detect_mult * \
-            max(self.test_session.desired_min_tx,
-                self.vpp_session.required_min_rx) / USEC_IN_SEC
+        timeout = (
+            self.test_session.detect_mult
+            * max(self.test_session.desired_min_tx, self.vpp_session.required_min_rx)
+            / USEC_IN_SEC
+        )
         self.test_session.send_packet(final)
         time_mark = time.time()
         e = self.vapi.wait_for_event(2 * timeout, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.down)
         time_to_event = time.time() - time_mark
-        self.assert_in_range(time_to_event, .9 * timeout,
-                             1.1 * timeout, "session timeout")
+        self.assert_in_range(
+            time_to_event, 0.9 * timeout, 1.1 * timeout, "session timeout"
+        )
 
     def test_modify_req_min_rx_halve(self):
-        """ modify session - halve required min rx """
+        """modify session - halve required min rx"""
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
-        self.test_session.update(desired_min_tx=10000,
-                                 required_min_rx=10000)
+        self.test_session.update(desired_min_tx=10000, required_min_rx=10000)
         self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         # halve required min rx
         old_required_min_rx = self.vpp_session.required_min_rx
         self.vpp_session.modify_parameters(
-            required_min_rx=self.vpp_session.required_min_rx // 2)
+            required_min_rx=self.vpp_session.required_min_rx // 2
+        )
         # now we wait 0.8*3*old-req-min-rx and the session should still be up
-        self.sleep(0.8 * self.vpp_session.detect_mult *
-                   old_required_min_rx / USEC_IN_SEC,
-                   "wait before finishing poll sequence")
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.sleep(
+            0.8 * self.vpp_session.detect_mult * old_required_min_rx / USEC_IN_SEC,
+            "wait before finishing poll sequence",
+        )
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
         p = wait_for_bfd_packet(self)
         # poll bit needs to be set
-        self.assertIn("P", p.sprintf("%BFD.flags%"),
-                      "Poll bit not set in BFD packet")
+        self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet")
         # finish poll sequence with final packet
         final = self.test_session.create_packet()
         final[BFD].flags = "F"
         self.test_session.send_packet(final)
         # now the session should time out under new conditions
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         before = time.time()
-        e = self.vapi.wait_for_event(
-            2 * detection_time, "bfd_udp_session_event")
+        e = self.vapi.wait_for_event(2 * detection_time, "bfd_udp_session_event")
         after = time.time()
-        self.assert_in_range(after - before,
-                             0.9 * detection_time,
-                             1.1 * detection_time,
-                             "time before bfd session goes down")
+        self.assert_in_range(
+            after - before,
+            0.9 * detection_time,
+            1.1 * detection_time,
+            "time before bfd session goes down",
+        )
         verify_event(self, e, expected_state=BFDState.down)
 
     def test_modify_detect_mult(self):
-        """ modify detect multiplier """
+        """modify detect multiplier"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
         self.vpp_session.modify_parameters(detect_mult=1)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(self.vpp_session.detect_mult,
-                          p[BFD].detect_mult,
-                          "detect mult")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            self.vpp_session.detect_mult, p[BFD].detect_mult, "detect mult"
+        )
         # poll bit must not be set
-        self.assertNotIn("P", p.sprintf("%BFD.flags%"),
-                         "Poll bit not set in BFD packet")
+        self.assertNotIn(
+            "P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet"
+        )
         self.vpp_session.modify_parameters(detect_mult=10)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(self.vpp_session.detect_mult,
-                          p[BFD].detect_mult,
-                          "detect mult")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            self.vpp_session.detect_mult, p[BFD].detect_mult, "detect mult"
+        )
         # poll bit must not be set
-        self.assertNotIn("P", p.sprintf("%BFD.flags%"),
-                         "Poll bit not set in BFD packet")
+        self.assertNotIn(
+            "P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet"
+        )
 
     def test_queued_poll(self):
-        """ test poll sequence queueing """
+        """test poll sequence queueing"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
         p = wait_for_bfd_packet(self)
         poll_sequence_start = time.time()
         poll_sequence_length_min = 0.5
         send_final_after = time.time() + poll_sequence_length_min
         # poll bit needs to be set
-        self.assertIn("P", p.sprintf("%BFD.flags%"),
-                      "Poll bit not set in BFD packet")
-        self.assert_equal(p[BFD].required_min_rx_interval,
-                          self.vpp_session.required_min_rx,
-                          "BFD required min rx interval")
+        self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet")
+        self.assert_equal(
+            p[BFD].required_min_rx_interval,
+            self.vpp_session.required_min_rx,
+            "BFD required min rx interval",
+        )
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
         # 2nd poll sequence should be queued now
         # don't send the reply back yet, wait for some time to emulate
         # longer round-trip time
@@ -1082,15 +1174,19 @@ class BFD4TestCase(VppTestCase):
         while time.time() < send_final_after:
             self.test_session.send_packet()
             p = wait_for_bfd_packet(self)
-            self.assert_equal(len(self.vapi.collect_events()), 0,
-                              "number of bfd events")
-            self.assert_equal(p[BFD].required_min_rx_interval,
-                              self.vpp_session.required_min_rx,
-                              "BFD required min rx interval")
+            self.assert_equal(
+                len(self.vapi.collect_events()), 0, "number of bfd events"
+            )
+            self.assert_equal(
+                p[BFD].required_min_rx_interval,
+                self.vpp_session.required_min_rx,
+                "BFD required min rx interval",
+            )
             packet_count += 1
             # poll bit must be set
-            self.assertIn("P", p.sprintf("%BFD.flags%"),
-                          "Poll bit not set in BFD packet")
+            self.assertIn(
+                "P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet"
+            )
         final = self.test_session.create_packet()
         final[BFD].flags = "F"
         self.test_session.send_packet(final)
@@ -1100,8 +1196,9 @@ class BFD4TestCase(VppTestCase):
         poll_no_2_started = False
         for dummy in range(2 * packet_count):
             p = wait_for_bfd_packet(self)
-            self.assert_equal(len(self.vapi.collect_events()), 0,
-                              "number of bfd events")
+            self.assert_equal(
+                len(self.vapi.collect_events()), 0, "number of bfd events"
+            )
             if "P" in p.sprintf("%BFD.flags%"):
                 poll_no_2_started = True
                 if time.time() < poll_sequence_start + poll_sequence_length:
@@ -1119,31 +1216,32 @@ class BFD4TestCase(VppTestCase):
         self.test_session.send_packet(final)
         p = wait_for_bfd_packet(self)
         # poll bit must not be set
-        self.assertNotIn("P", p.sprintf("%BFD.flags%"),
-                         "Poll bit set in BFD packet")
+        self.assertNotIn("P", p.sprintf("%BFD.flags%"), "Poll bit set in BFD packet")
 
     # returning inconsistent results requiring retries in per-patch tests
     @unittest.skipUnless(config.extended, "part of extended tests")
     def test_poll_response(self):
-        """ test correct response to control frame with poll bit set """
+        """test correct response to control frame with poll bit set"""
         bfd_session_up(self)
         poll = self.test_session.create_packet()
         poll[BFD].flags = "P"
         self.test_session.send_packet(poll)
         final = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            self, pcap_time_min=time.time() - self.vpp_clock_offset
+        )
         self.assertIn("F", final.sprintf("%BFD.flags%"))
 
     def test_no_periodic_if_remote_demand(self):
-        """ no periodic frames outside poll sequence if remote demand set """
+        """no periodic frames outside poll sequence if remote demand set"""
         bfd_session_up(self)
         demand = self.test_session.create_packet()
         demand[BFD].flags = "D"
         self.test_session.send_packet(demand)
-        transmit_time = 0.9 \
-            * max(self.vpp_session.required_min_rx,
-                  self.test_session.desired_min_tx) \
+        transmit_time = (
+            0.9
+            * max(self.vpp_session.required_min_rx, self.test_session.desired_min_tx)
             / USEC_IN_SEC
+        )
         count = 0
         for dummy in range(self.test_session.detect_mult * 2):
             self.sleep(transmit_time)
@@ -1161,7 +1259,7 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(len(events), 0, "number of events received")
 
     def test_echo_looped_back(self):
-        """ echo packets looped back """
+        """echo packets looped back"""
         bfd_session_up(self)
         stats_before = bfd_grab_stats_snapshot(self)
         self.pg0.enable_capture()
@@ -1169,14 +1267,14 @@ class BFD4TestCase(VppTestCase):
         # random source port low enough to increment a few times..
         udp_sport_tx = randint(1, 50000)
         udp_sport_rx = udp_sport_tx
-        echo_packet = (Ether(src=self.pg0.remote_mac,
-                             dst=self.pg0.local_mac) /
-                       IP(src=self.pg0.remote_ip4,
-                          dst=self.pg0.remote_ip4) /
-                       UDP(dport=BFD.udp_dport_echo) /
-                       Raw("this should be looped back"))
+        echo_packet = (
+            Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
+            / IP(src=self.pg0.remote_ip4, dst=self.pg0.remote_ip4)
+            / UDP(dport=BFD.udp_dport_echo)
+            / Raw("this should be looped back")
+        )
         for dummy in range(echo_packet_count):
-            self.sleep(.01, "delay between echo packets")
+            self.sleep(0.01, "delay between echo packets")
             echo_packet[UDP].sport = udp_sport_tx
             udp_sport_tx += 1
             self.logger.debug(ppp("Sending packet:", echo_packet))
@@ -1189,8 +1287,7 @@ class BFD4TestCase(VppTestCase):
             p = self.pg0.wait_for_packet(1)
             self.logger.debug(ppp("Got packet:", p))
             ether = p[Ether]
-            self.assert_equal(self.pg0.remote_mac,
-                              ether.dst, "Destination MAC")
+            self.assert_equal(self.pg0.remote_mac, ether.dst, "Destination MAC")
             self.assert_equal(self.pg0.local_mac, ether.src, "Source MAC")
             ip = p[IP]
             self.assert_equal(self.pg0.remote_ip4, ip.dst, "Destination IP")
@@ -1199,50 +1296,57 @@ class BFD4TestCase(VppTestCase):
                 bfd_control_packets_rx += 1
                 continue
             self.assert_equal(self.pg0.remote_ip4, ip.src, "Source IP")
-            self.assert_equal(udp.dport, BFD.udp_dport_echo,
-                              "UDP destination port")
+            self.assert_equal(udp.dport, BFD.udp_dport_echo, "UDP destination port")
             self.assert_equal(udp.sport, udp_sport_rx, "UDP source port")
             udp_sport_rx += 1
             # need to compare the hex payload here, otherwise BFD_vpp_echo
             # gets in way
-            self.assertEqual(scapy.compat.raw(p[UDP].payload),
-                             scapy.compat.raw(echo_packet[UDP].payload),
-                             "Received packet is not the echo packet sent")
+            self.assertEqual(
+                scapy.compat.raw(p[UDP].payload),
+                scapy.compat.raw(echo_packet[UDP].payload),
+                "Received packet is not the echo packet sent",
+            )
             counter += 1
-        self.assert_equal(udp_sport_tx, udp_sport_rx, "UDP source port (== "
-                          "ECHO packet identifier for test purposes)")
+        self.assert_equal(
+            udp_sport_tx,
+            udp_sport_rx,
+            "UDP source port (== ECHO packet identifier for test purposes)",
+        )
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
+        self.assertEqual(0, diff.rx, "RX counter bumped but no BFD packets sent")
+        self.assertEqual(bfd_control_packets_rx, diff.tx, "TX counter incorrect")
         self.assertEqual(
-            0, diff.rx, "RX counter bumped but no BFD packets sent")
+            0, diff.rx_echo, "RX echo counter bumped but no BFD session exists"
+        )
         self.assertEqual(
-            bfd_control_packets_rx, diff.tx, "TX counter incorrect")
-        self.assertEqual(0, diff.rx_echo,
-                         "RX echo counter bumped but no BFD session exists")
-        self.assertEqual(0, diff.tx_echo,
-                         "TX echo counter bumped but no BFD session exists")
+            0, diff.tx_echo, "TX echo counter bumped but no BFD session exists"
+        )
 
     def test_echo(self):
-        """ echo function """
+        """echo function"""
         stats_before = bfd_grab_stats_snapshot(self)
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         # echo shouldn't work without echo source set
         for dummy in range(10):
             sleep = self.vpp_session.required_min_rx / USEC_IN_SEC
             self.sleep(sleep, "delay before sending bfd packet")
             self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(p[BFD].required_min_rx_interval,
-                          self.vpp_session.required_min_rx,
-                          "BFD required min rx interval")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            p[BFD].required_min_rx_interval,
+            self.vpp_session.required_min_rx,
+            "BFD required min rx interval",
+        )
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         echo_seen = False
         # should be turned on - loopback echo packets
         for dummy in range(3):
@@ -1251,13 +1355,18 @@ class BFD4TestCase(VppTestCase):
                 p = self.pg0.wait_for_packet(1)
                 self.logger.debug(ppp("Got packet:", p))
                 if p[UDP].dport == BFD.udp_dport_echo:
-                    self.assert_equal(
-                        p[IP].dst, self.pg0.local_ip4, "BFD ECHO dst IP")
-                    self.assertNotEqual(p[IP].src, self.loopback0.local_ip4,
-                                        "BFD ECHO src IP equal to loopback IP")
+                    self.assert_equal(p[IP].dst, self.pg0.local_ip4, "BFD ECHO dst IP")
+                    self.assertNotEqual(
+                        p[IP].src,
+                        self.loopback0.local_ip4,
+                        "BFD ECHO src IP equal to loopback IP",
+                    )
                     self.logger.debug(ppp("Looping back packet:", p))
-                    self.assert_equal(p[Ether].dst, self.pg0.remote_mac,
-                                      "ECHO packet destination MAC address")
+                    self.assert_equal(
+                        p[Ether].dst,
+                        self.pg0.remote_mac,
+                        "ECHO packet destination MAC address",
+                    )
                     p[Ether].dst = self.pg0.local_mac
                     self.pg0.add_stream(p)
                     self.test_session.rx_packets_echo += 1
@@ -1268,8 +1377,8 @@ class BFD4TestCase(VppTestCase):
                     self.test_session.rx_packets += 1
                     if echo_seen:
                         self.assertGreaterEqual(
-                            p[BFD].required_min_rx_interval,
-                            1000000)
+                            p[BFD].required_min_rx_interval, 1000000
+                        )
                     if "P" in p.sprintf("%BFD.flags%"):
                         final = self.test_session.create_packet()
                         final[BFD].flags = "F"
@@ -1277,34 +1386,45 @@ class BFD4TestCase(VppTestCase):
                 else:
                     raise Exception(ppp("Received unknown packet:", p))
 
-                self.assert_equal(len(self.vapi.collect_events()), 0,
-                                  "number of bfd events")
+                self.assert_equal(
+                    len(self.vapi.collect_events()), 0, "number of bfd events"
+                )
             self.test_session.send_packet()
         self.assertTrue(echo_seen, "No echo packets received")
 
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
         # our rx is vpp tx and vice versa, also tolerate one packet off
-        self.assert_in_range(self.test_session.tx_packets,
-                             diff.rx - 1, diff.rx + 1, "RX counter")
-        self.assert_in_range(self.test_session.rx_packets,
-                             diff.tx - 1, diff.tx + 1, "TX counter")
-        self.assert_in_range(self.test_session.tx_packets_echo,
-                             diff.rx_echo - 1, diff.rx_echo + 1,
-                             "RX echo counter")
-        self.assert_in_range(self.test_session.rx_packets_echo,
-                             diff.tx_echo - 1, diff.tx_echo + 1,
-                             "TX echo counter")
+        self.assert_in_range(
+            self.test_session.tx_packets, diff.rx - 1, diff.rx + 1, "RX counter"
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets, diff.tx - 1, diff.tx + 1, "TX counter"
+        )
+        self.assert_in_range(
+            self.test_session.tx_packets_echo,
+            diff.rx_echo - 1,
+            diff.rx_echo + 1,
+            "RX echo counter",
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets_echo,
+            diff.tx_echo - 1,
+            diff.tx_echo + 1,
+            "TX echo counter",
+        )
 
     def test_echo_fail(self):
-        """ session goes down if echo function fails """
+        """session goes down if echo function fails"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         # echo function should be used now, but we will drop the echo packets
         verified_diag = False
         for dummy in range(3):
@@ -1318,15 +1438,15 @@ class BFD4TestCase(VppTestCase):
                 elif p.haslayer(BFD):
                     if "P" in p.sprintf("%BFD.flags%"):
                         self.assertGreaterEqual(
-                            p[BFD].required_min_rx_interval,
-                            1000000)
+                            p[BFD].required_min_rx_interval, 1000000
+                        )
                         final = self.test_session.create_packet()
                         final[BFD].flags = "F"
                         self.test_session.send_packet(final)
                     if p[BFD].state == BFDState.down:
-                        self.assert_equal(p[BFD].diag,
-                                          BFDDiagCode.echo_function_failed,
-                                          BFDDiagCode)
+                        self.assert_equal(
+                            p[BFD].diag, BFDDiagCode.echo_function_failed, BFDDiagCode
+                        )
                         verified_diag = True
                 else:
                     raise Exception(ppp("Received unknown packet:", p))
@@ -1337,12 +1457,11 @@ class BFD4TestCase(VppTestCase):
         self.assertTrue(verified_diag, "Incorrect diagnostics code received")
 
     def test_echo_stop(self):
-        """ echo function stops if peer sets required min echo rx zero """
+        """echo function stops if peer sets required min echo rx zero"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         # wait for first echo packet
         while True:
             p = self.pg0.wait_for_packet(1)
@@ -1362,19 +1481,17 @@ class BFD4TestCase(VppTestCase):
         self.test_session.send_packet()
         # echo packets shouldn't arrive anymore
         for dummy in range(5):
-            wait_for_bfd_packet(
-                self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
             self.test_session.send_packet()
             events = self.vapi.collect_events()
             self.assert_equal(len(events), 0, "number of bfd events")
 
     def test_echo_source_removed(self):
-        """ echo function stops if echo source is removed """
+        """echo function stops if echo source is removed"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         # wait for first echo packet
         while True:
             p = self.pg0.wait_for_packet(1)
@@ -1394,18 +1511,16 @@ class BFD4TestCase(VppTestCase):
         self.test_session.send_packet()
         # echo packets shouldn't arrive anymore
         for dummy in range(5):
-            wait_for_bfd_packet(
-                self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
             self.test_session.send_packet()
             events = self.vapi.collect_events()
             self.assert_equal(len(events), 0, "number of bfd events")
 
     def test_stale_echo(self):
-        """ stale echo packets don't keep a session up """
+        """stale echo packets don't keep a session up"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         self.test_session.send_packet()
         # should be turned on - loopback echo packets
         echo_packet = None
@@ -1417,8 +1532,12 @@ class BFD4TestCase(VppTestCase):
                 if echo_packet is None:
                     self.logger.debug(ppp("Got first echo packet:", p))
                     echo_packet = p
-                    timeout_at = time.time() + self.vpp_session.detect_mult * \
-                        self.test_session.required_min_echo_rx / USEC_IN_SEC
+                    timeout_at = (
+                        time.time()
+                        + self.vpp_session.detect_mult
+                        * self.test_session.required_min_echo_rx
+                        / USEC_IN_SEC
+                    )
                 else:
                     self.logger.debug(ppp("Got followup echo packet:", p))
                 self.logger.debug(ppp("Looping back first echo packet:", p))
@@ -1434,15 +1553,18 @@ class BFD4TestCase(VppTestCase):
                 if p[BFD].state == BFDState.down:
                     self.assertIsNotNone(
                         timeout_at,
-                        "Session went down before first echo packet received")
+                        "Session went down before first echo packet received",
+                    )
                     now = time.time()
                     self.assertGreaterEqual(
-                        now, timeout_at,
-                        "Session timeout at %s, but is expected at %s" %
-                        (now, timeout_at))
-                    self.assert_equal(p[BFD].diag,
-                                      BFDDiagCode.echo_function_failed,
-                                      BFDDiagCode)
+                        now,
+                        timeout_at,
+                        "Session timeout at %s, but is expected at %s"
+                        % (now, timeout_at),
+                    )
+                    self.assert_equal(
+                        p[BFD].diag, BFDDiagCode.echo_function_failed, BFDDiagCode
+                    )
                     events = self.vapi.collect_events()
                     self.assert_equal(len(events), 1, "number of bfd events")
                     self.assert_equal(events[0].state, BFDState.down, BFDState)
@@ -1454,11 +1576,10 @@ class BFD4TestCase(VppTestCase):
         self.assertTrue(timeout_ok, "Expected timeout event didn't occur")
 
     def test_invalid_echo_checksum(self):
-        """ echo packets with invalid checksum don't keep a session up """
+        """echo packets with invalid checksum don't keep a session up"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         self.test_session.send_packet()
         # should be turned on - loopback echo packets
         timeout_at = None
@@ -1468,8 +1589,12 @@ class BFD4TestCase(VppTestCase):
             if p[UDP].dport == BFD.udp_dport_echo:
                 self.logger.debug(ppp("Got echo packet:", p))
                 if timeout_at is None:
-                    timeout_at = time.time() + self.vpp_session.detect_mult * \
-                        self.test_session.required_min_echo_rx / USEC_IN_SEC
+                    timeout_at = (
+                        time.time()
+                        + self.vpp_session.detect_mult
+                        * self.test_session.required_min_echo_rx
+                        / USEC_IN_SEC
+                    )
                 p[BFD_vpp_echo].checksum = getrandbits(64)
                 p[Ether].dst = self.pg0.local_mac
                 self.logger.debug(ppp("Looping back modified echo packet:", p))
@@ -1484,15 +1609,18 @@ class BFD4TestCase(VppTestCase):
                 if p[BFD].state == BFDState.down:
                     self.assertIsNotNone(
                         timeout_at,
-                        "Session went down before first echo packet received")
+                        "Session went down before first echo packet received",
+                    )
                     now = time.time()
                     self.assertGreaterEqual(
-                        now, timeout_at,
-                        "Session timeout at %s, but is expected at %s" %
-                        (now, timeout_at))
-                    self.assert_equal(p[BFD].diag,
-                                      BFDDiagCode.echo_function_failed,
-                                      BFDDiagCode)
+                        now,
+                        timeout_at,
+                        "Session timeout at %s, but is expected at %s"
+                        % (now, timeout_at),
+                    )
+                    self.assert_equal(
+                        p[BFD].diag, BFDDiagCode.echo_function_failed, BFDDiagCode
+                    )
                     events = self.vapi.collect_events()
                     self.assert_equal(len(events), 1, "number of bfd events")
                     self.assert_equal(events[0].state, BFDState.down, BFDState)
@@ -1504,7 +1632,7 @@ class BFD4TestCase(VppTestCase):
         self.assertTrue(timeout_ok, "Expected timeout event didn't occur")
 
     def test_admin_up_down(self):
-        """ put session admin-up and admin-down """
+        """put session admin-up and admin-down"""
         bfd_session_up(self)
         self.vpp_session.admin_down()
         self.pg0.enable_capture()
@@ -1523,33 +1651,30 @@ class BFD4TestCase(VppTestCase):
         self.test_session.update(state=BFDState.down)
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.down)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         self.assert_equal(p[BFD].state, BFDState.down, BFDState)
         self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         self.assert_equal(p[BFD].state, BFDState.init, BFDState)
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.init)
         self.test_session.update(state=BFDState.up)
         self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         self.assert_equal(p[BFD].state, BFDState.up, BFDState)
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.up)
 
     def test_config_change_remote_demand(self):
-        """ configuration change while peer in demand mode """
+        """configuration change while peer in demand mode"""
         bfd_session_up(self)
         demand = self.test_session.create_packet()
         demand[BFD].flags = "D"
         self.test_session.send_packet(demand)
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         # poll bit must be set
         self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set")
         # terminate poll sequence
@@ -1557,10 +1682,11 @@ class BFD4TestCase(VppTestCase):
         final[BFD].flags = "D+F"
         self.test_session.send_packet(final)
         # vpp should be quiet now again
-        transmit_time = 0.9 \
-            * max(self.vpp_session.required_min_rx,
-                  self.test_session.desired_min_tx) \
+        transmit_time = (
+            0.9
+            * max(self.vpp_session.required_min_rx, self.test_session.desired_min_tx)
             / USEC_IN_SEC
+        )
         count = 0
         for dummy in range(self.test_session.detect_mult * 2):
             self.sleep(transmit_time)
@@ -1578,7 +1704,7 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(len(events), 0, "number of events received")
 
     def test_intf_deleted(self):
-        """ interface with bfd session deleted """
+        """interface with bfd session deleted"""
         intf = VppLoInterface(self)
         intf.config_ip4()
         intf.admin_up()
@@ -1595,7 +1721,7 @@ class BFD4TestCase(VppTestCase):
 @tag_run_solo
 @tag_fixme_vpp_workers
 class BFD6TestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (IPv6) """
+    """Bidirectional Forwarding Detection (BFD) (IPv6)"""
 
     pg0 = None
     vpp_clock_offset = None
@@ -1631,11 +1757,11 @@ class BFD6TestCase(VppTestCase):
         self.vapi.want_bfd_events()
         self.pg0.enable_capture()
         try:
-            self.bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-            self.bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
-            self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                                self.pg0.remote_ip6,
-                                                af=AF_INET6)
+            self.bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+            self.bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
+            self.vpp_session = VppBFDUDPSession(
+                self, self.pg0, self.pg0.remote_ip6, af=AF_INET6
+            )
             self.vpp_session.add_vpp_config()
             self.vpp_session.admin_up()
             self.test_session = BFDTestSession(self, self.pg0, AF_INET6)
@@ -1651,26 +1777,29 @@ class BFD6TestCase(VppTestCase):
         super(BFD6TestCase, self).tearDown()
 
     def test_session_up(self):
-        """ bring BFD session up """
+        """bring BFD session up"""
         bfd_session_up(self)
-        bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-        bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
+        bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+        bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
         self.assert_equal(bfd_udp4_sessions, self.bfd_udp4_sessions)
         self.assert_equal(bfd_udp6_sessions - self.bfd_udp6_sessions, 1)
 
     def test_session_up_by_ip(self):
-        """ bring BFD session up - first frame looked up by address pair """
+        """bring BFD session up - first frame looked up by address pair"""
         self.logger.info("BFD: Sending Slow control frame")
         self.test_session.update(my_discriminator=randint(0, 40000000))
         self.test_session.send_packet()
         self.pg0.enable_capture()
         p = self.pg0.wait_for_packet(1)
-        self.assert_equal(p[BFD].your_discriminator,
-                          self.test_session.my_discriminator,
-                          "BFD - your discriminator")
+        self.assert_equal(
+            p[BFD].your_discriminator,
+            self.test_session.my_discriminator,
+            "BFD - your discriminator",
+        )
         self.assert_equal(p[BFD].state, BFDState.init, BFDState)
-        self.test_session.update(your_discriminator=p[BFD].my_discriminator,
-                                 state=BFDState.up)
+        self.test_session.update(
+            your_discriminator=p[BFD].my_discriminator, state=BFDState.up
+        )
         self.logger.info("BFD: Waiting for event")
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.init)
@@ -1685,17 +1814,16 @@ class BFD6TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_hold_up(self):
-        """ hold BFD session up """
+        """hold BFD session up"""
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             wait_for_bfd_packet(self)
             self.test_session.send_packet()
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_echo_looped_back(self):
-        """ echo packets looped back """
+        """echo packets looped back"""
         bfd_session_up(self)
         stats_before = bfd_grab_stats_snapshot(self)
         self.pg0.enable_capture()
@@ -1703,14 +1831,14 @@ class BFD6TestCase(VppTestCase):
         # random source port low enough to increment a few times..
         udp_sport_tx = randint(1, 50000)
         udp_sport_rx = udp_sport_tx
-        echo_packet = (Ether(src=self.pg0.remote_mac,
-                             dst=self.pg0.local_mac) /
-                       IPv6(src=self.pg0.remote_ip6,
-                            dst=self.pg0.remote_ip6) /
-                       UDP(dport=BFD.udp_dport_echo) /
-                       Raw("this should be looped back"))
+        echo_packet = (
+            Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg0.remote_ip6)
+            / UDP(dport=BFD.udp_dport_echo)
+            / Raw("this should be looped back")
+        )
         for dummy in range(echo_packet_count):
-            self.sleep(.01, "delay between echo packets")
+            self.sleep(0.01, "delay between echo packets")
             echo_packet[UDP].sport = udp_sport_tx
             udp_sport_tx += 1
             self.logger.debug(ppp("Sending packet:", echo_packet))
@@ -1722,8 +1850,7 @@ class BFD6TestCase(VppTestCase):
             p = self.pg0.wait_for_packet(1)
             self.logger.debug(ppp("Got packet:", p))
             ether = p[Ether]
-            self.assert_equal(self.pg0.remote_mac,
-                              ether.dst, "Destination MAC")
+            self.assert_equal(self.pg0.remote_mac, ether.dst, "Destination MAC")
             self.assert_equal(self.pg0.local_mac, ether.src, "Source MAC")
             ip = p[IPv6]
             self.assert_equal(self.pg0.remote_ip6, ip.dst, "Destination IP")
@@ -1732,50 +1859,57 @@ class BFD6TestCase(VppTestCase):
                 bfd_control_packets_rx += 1
                 continue
             self.assert_equal(self.pg0.remote_ip6, ip.src, "Source IP")
-            self.assert_equal(udp.dport, BFD.udp_dport_echo,
-                              "UDP destination port")
+            self.assert_equal(udp.dport, BFD.udp_dport_echo, "UDP destination port")
             self.assert_equal(udp.sport, udp_sport_rx, "UDP source port")
             udp_sport_rx += 1
             # need to compare the hex payload here, otherwise BFD_vpp_echo
             # gets in way
-            self.assertEqual(scapy.compat.raw(p[UDP].payload),
-                             scapy.compat.raw(echo_packet[UDP].payload),
-                             "Received packet is not the echo packet sent")
+            self.assertEqual(
+                scapy.compat.raw(p[UDP].payload),
+                scapy.compat.raw(echo_packet[UDP].payload),
+                "Received packet is not the echo packet sent",
+            )
             counter += 1
-        self.assert_equal(udp_sport_tx, udp_sport_rx, "UDP source port (== "
-                          "ECHO packet identifier for test purposes)")
+        self.assert_equal(
+            udp_sport_tx,
+            udp_sport_rx,
+            "UDP source port (== ECHO packet identifier for test purposes)",
+        )
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
+        self.assertEqual(0, diff.rx, "RX counter bumped but no BFD packets sent")
+        self.assertEqual(bfd_control_packets_rx, diff.tx, "TX counter incorrect")
         self.assertEqual(
-            0, diff.rx, "RX counter bumped but no BFD packets sent")
-        self.assertEqual(bfd_control_packets_rx,
-                         diff.tx, "TX counter incorrect")
-        self.assertEqual(0, diff.rx_echo,
-                         "RX echo counter bumped but no BFD session exists")
-        self.assertEqual(0, diff.tx_echo,
-                         "TX echo counter bumped but no BFD session exists")
+            0, diff.rx_echo, "RX echo counter bumped but no BFD session exists"
+        )
+        self.assertEqual(
+            0, diff.tx_echo, "TX echo counter bumped but no BFD session exists"
+        )
 
     def test_echo(self):
-        """ echo function """
+        """echo function"""
         stats_before = bfd_grab_stats_snapshot(self)
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         # echo shouldn't work without echo source set
         for dummy in range(10):
             sleep = self.vpp_session.required_min_rx / USEC_IN_SEC
             self.sleep(sleep, "delay before sending bfd packet")
             self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(p[BFD].required_min_rx_interval,
-                          self.vpp_session.required_min_rx,
-                          "BFD required min rx interval")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            p[BFD].required_min_rx_interval,
+            self.vpp_session.required_min_rx,
+            "BFD required min rx interval",
+        )
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         echo_seen = False
         # should be turned on - loopback echo packets
         for dummy in range(3):
@@ -1785,12 +1919,19 @@ class BFD6TestCase(VppTestCase):
                 self.logger.debug(ppp("Got packet:", p))
                 if p[UDP].dport == BFD.udp_dport_echo:
                     self.assert_equal(
-                        p[IPv6].dst, self.pg0.local_ip6, "BFD ECHO dst IP")
-                    self.assertNotEqual(p[IPv6].src, self.loopback0.local_ip6,
-                                        "BFD ECHO src IP equal to loopback IP")
+                        p[IPv6].dst, self.pg0.local_ip6, "BFD ECHO dst IP"
+                    )
+                    self.assertNotEqual(
+                        p[IPv6].src,
+                        self.loopback0.local_ip6,
+                        "BFD ECHO src IP equal to loopback IP",
+                    )
                     self.logger.debug(ppp("Looping back packet:", p))
-                    self.assert_equal(p[Ether].dst, self.pg0.remote_mac,
-                                      "ECHO packet destination MAC address")
+                    self.assert_equal(
+                        p[Ether].dst,
+                        self.pg0.remote_mac,
+                        "ECHO packet destination MAC address",
+                    )
                     self.test_session.rx_packets_echo += 1
                     self.test_session.tx_packets_echo += 1
                     p[Ether].dst = self.pg0.local_mac
@@ -1801,8 +1942,8 @@ class BFD6TestCase(VppTestCase):
                     self.test_session.rx_packets += 1
                     if echo_seen:
                         self.assertGreaterEqual(
-                            p[BFD].required_min_rx_interval,
-                            1000000)
+                            p[BFD].required_min_rx_interval, 1000000
+                        )
                     if "P" in p.sprintf("%BFD.flags%"):
                         final = self.test_session.create_packet()
                         final[BFD].flags = "F"
@@ -1810,33 +1951,41 @@ class BFD6TestCase(VppTestCase):
                 else:
                     raise Exception(ppp("Received unknown packet:", p))
 
-                self.assert_equal(len(self.vapi.collect_events()), 0,
-                                  "number of bfd events")
+                self.assert_equal(
+                    len(self.vapi.collect_events()), 0, "number of bfd events"
+                )
             self.test_session.send_packet()
         self.assertTrue(echo_seen, "No echo packets received")
 
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
         # our rx is vpp tx and vice versa, also tolerate one packet off
-        self.assert_in_range(self.test_session.tx_packets,
-                             diff.rx - 1, diff.rx + 1, "RX counter")
-        self.assert_in_range(self.test_session.rx_packets,
-                             diff.tx - 1, diff.tx + 1, "TX counter")
-        self.assert_in_range(self.test_session.tx_packets_echo,
-                             diff.rx_echo - 1, diff.rx_echo + 1,
-                             "RX echo counter")
-        self.assert_in_range(self.test_session.rx_packets_echo,
-                             diff.tx_echo - 1, diff.tx_echo + 1,
-                             "TX echo counter")
+        self.assert_in_range(
+            self.test_session.tx_packets, diff.rx - 1, diff.rx + 1, "RX counter"
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets, diff.tx - 1, diff.tx + 1, "TX counter"
+        )
+        self.assert_in_range(
+            self.test_session.tx_packets_echo,
+            diff.rx_echo - 1,
+            diff.rx_echo + 1,
+            "RX echo counter",
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets_echo,
+            diff.tx_echo - 1,
+            diff.tx_echo + 1,
+            "TX echo counter",
+        )
 
     def test_intf_deleted(self):
-        """ interface with bfd session deleted """
+        """interface with bfd session deleted"""
         intf = VppLoInterface(self)
         intf.config_ip6()
         intf.admin_up()
         sw_if_index = intf.sw_if_index
-        vpp_session = VppBFDUDPSession(
-            self, intf, intf.remote_ip6, af=AF_INET6)
+        vpp_session = VppBFDUDPSession(self, intf, intf.remote_ip6, af=AF_INET6)
         vpp_session.add_vpp_config()
         vpp_session.admin_up()
         intf.remove_vpp_config()
@@ -1847,7 +1996,7 @@ class BFD6TestCase(VppTestCase):
 
 @tag_run_solo
 class BFDFIBTestCase(VppTestCase):
-    """ BFD-FIB interactions (IPv6) """
+    """BFD-FIB interactions (IPv6)"""
 
     vpp_session = None
     test_session = None
@@ -1880,40 +2029,48 @@ class BFDFIBTestCase(VppTestCase):
 
     @staticmethod
     def pkt_is_not_data_traffic(p):
-        """ not data traffic implies BFD or the usual IPv6 ND/RA"""
+        """not data traffic implies BFD or the usual IPv6 ND/RA"""
         if p.haslayer(BFD) or is_ipv6_misc(p):
             return True
         return False
 
     def test_session_with_fib(self):
-        """ BFD-FIB interactions """
+        """BFD-FIB interactions"""
 
         # packets to match against both of the routes
-        p = [(Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-              IPv6(src="3001::1", dst="2001::1") /
-              UDP(sport=1234, dport=1234) /
-              Raw(b'\xa5' * 100)),
-             (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-              IPv6(src="3001::1", dst="2002::1") /
-              UDP(sport=1234, dport=1234) /
-              Raw(b'\xa5' * 100))]
+        p = [
+            (
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / IPv6(src="3001::1", dst="2001::1")
+                / UDP(sport=1234, dport=1234)
+                / Raw(b"\xa5" * 100)
+            ),
+            (
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / IPv6(src="3001::1", dst="2002::1")
+                / UDP(sport=1234, dport=1234)
+                / Raw(b"\xa5" * 100)
+            ),
+        ]
 
         # A recursive and a non-recursive route via a next-hop that
         # will have a BFD session
-        ip_2001_s_64 = VppIpRoute(self, "2001::", 64,
-                                  [VppRoutePath(self.pg0.remote_ip6,
-                                                self.pg0.sw_if_index)])
-        ip_2002_s_64 = VppIpRoute(self, "2002::", 64,
-                                  [VppRoutePath(self.pg0.remote_ip6,
-                                                0xffffffff)])
+        ip_2001_s_64 = VppIpRoute(
+            self,
+            "2001::",
+            64,
+            [VppRoutePath(self.pg0.remote_ip6, self.pg0.sw_if_index)],
+        )
+        ip_2002_s_64 = VppIpRoute(
+            self, "2002::", 64, [VppRoutePath(self.pg0.remote_ip6, 0xFFFFFFFF)]
+        )
         ip_2001_s_64.add_vpp_config()
         ip_2002_s_64.add_vpp_config()
 
         # bring the session up now the routes are present
-        self.vpp_session = VppBFDUDPSession(self,
-                                            self.pg0,
-                                            self.pg0.remote_ip6,
-                                            af=AF_INET6)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(self, self.pg0, AF_INET6)
@@ -1925,10 +2082,9 @@ class BFDFIBTestCase(VppTestCase):
         self.pg_start()
         for packet in p:
             captured = self.pg0.wait_for_packet(
-                1,
-                filter_out_fn=self.pkt_is_not_data_traffic)
-            self.assertEqual(captured[IPv6].dst,
-                             packet[IPv6].dst)
+                1, filter_out_fn=self.pkt_is_not_data_traffic
+            )
+            self.assertEqual(captured[IPv6].dst, packet[IPv6].dst)
 
         # session is up - traffic is dropped
         bfd_session_down(self)
@@ -1945,15 +2101,14 @@ class BFDFIBTestCase(VppTestCase):
         self.pg_start()
         for packet in p:
             captured = self.pg0.wait_for_packet(
-                1,
-                filter_out_fn=self.pkt_is_not_data_traffic)
-            self.assertEqual(captured[IPv6].dst,
-                             packet[IPv6].dst)
+                1, filter_out_fn=self.pkt_is_not_data_traffic
+            )
+            self.assertEqual(captured[IPv6].dst, packet[IPv6].dst)
 
 
 @unittest.skipUnless(config.extended, "part of extended tests")
 class BFDTunTestCase(VppTestCase):
-    """ BFD over GRE tunnel """
+    """BFD over GRE tunnel"""
 
     vpp_session = None
     test_session = None
@@ -1986,42 +2141,44 @@ class BFDTunTestCase(VppTestCase):
 
     @staticmethod
     def pkt_is_not_data_traffic(p):
-        """ not data traffic implies BFD or the usual IPv6 ND/RA"""
+        """not data traffic implies BFD or the usual IPv6 ND/RA"""
         if p.haslayer(BFD) or is_ipv6_misc(p):
             return True
         return False
 
     def test_bfd_o_gre(self):
-        """ BFD-o-GRE  """
+        """BFD-o-GRE"""
 
         # A GRE interface over which to run a BFD session
-        gre_if = VppGreInterface(self,
-                                 self.pg0.local_ip4,
-                                 self.pg0.remote_ip4)
+        gre_if = VppGreInterface(self, self.pg0.local_ip4, self.pg0.remote_ip4)
         gre_if.add_vpp_config()
         gre_if.admin_up()
         gre_if.config_ip4()
 
         # bring the session up now the routes are present
-        self.vpp_session = VppBFDUDPSession(self,
-                                            gre_if,
-                                            gre_if.remote_ip4,
-                                            is_tunnel=True)
+        self.vpp_session = VppBFDUDPSession(
+            self, gre_if, gre_if.remote_ip4, is_tunnel=True
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
 
         self.test_session = BFDTestSession(
-            self, gre_if, AF_INET,
-            tunnel_header=(IP(src=self.pg0.remote_ip4,
-                              dst=self.pg0.local_ip4) /
-                           GRE()),
-            phy_interface=self.pg0)
+            self,
+            gre_if,
+            AF_INET,
+            tunnel_header=(IP(src=self.pg0.remote_ip4, dst=self.pg0.local_ip4) / GRE()),
+            phy_interface=self.pg0,
+        )
 
         # packets to match against both of the routes
-        p = [(Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-              IP(src=self.pg0.remote_ip4, dst=gre_if.remote_ip4) /
-              UDP(sport=1234, dport=1234) /
-              Raw(b'\xa5' * 100))]
+        p = [
+            (
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / IP(src=self.pg0.remote_ip4, dst=gre_if.remote_ip4)
+                / UDP(sport=1234, dport=1234)
+                / Raw(b"\xa5" * 100)
+            )
+        ]
 
         # session is up - traffic passes
         bfd_session_up(self)
@@ -2034,7 +2191,7 @@ class BFDTunTestCase(VppTestCase):
 
 @tag_run_solo
 class BFDSHA1TestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (SHA1 auth) """
+    """Bidirectional Forwarding Detection (BFD) (SHA1 auth)"""
 
     pg0 = None
     vpp_clock_offset = None
@@ -2072,31 +2229,39 @@ class BFDSHA1TestCase(VppTestCase):
         super(BFDSHA1TestCase, self).tearDown()
 
     def test_session_up(self):
-        """ bring BFD session up """
+        """bring BFD session up"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4,
-                                            sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
 
     def test_hold_up(self):
-        """ hold BFD session up """
+        """hold BFD session up"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4,
-                                            sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             wait_for_bfd_packet(self)
@@ -2104,19 +2269,23 @@ class BFDSHA1TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_hold_up_meticulous(self):
-        """ hold BFD session up - meticulous auth """
-        key = self.factory.create_random_key(
-            self, BFDAuthType.meticulous_keyed_sha1)
+        """hold BFD session up - meticulous auth"""
+        key = self.factory.create_random_key(self, BFDAuthType.meticulous_keyed_sha1)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         # specify sequence number so that it wraps
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
             bfd_key_id=self.vpp_session.bfd_key_id,
-            our_seq_number=0xFFFFFFFF - 4)
+            our_seq_number=0xFFFFFFFF - 4,
+        )
         bfd_session_up(self)
         for dummy in range(30):
             wait_for_bfd_packet(self)
@@ -2125,35 +2294,47 @@ class BFDSHA1TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_send_bad_seq_number(self):
-        """ session is not kept alive by msgs with bad sequence numbers"""
-        key = self.factory.create_random_key(
-            self, BFDAuthType.meticulous_keyed_sha1)
+        """session is not kept alive by msgs with bad sequence numbers"""
+        key = self.factory.create_random_key(self, BFDAuthType.meticulous_keyed_sha1)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         send_until = time.time() + 2 * detection_time
         while time.time() < send_until:
             self.test_session.send_packet()
-            self.sleep(0.7 * self.vpp_session.required_min_rx / USEC_IN_SEC,
-                       "time between bfd packets")
+            self.sleep(
+                0.7 * self.vpp_session.required_min_rx / USEC_IN_SEC,
+                "time between bfd packets",
+            )
         e = self.vapi.collect_events()
         # session should be down now, because the sequence numbers weren't
         # updated
         self.assert_equal(len(e), 1, "number of bfd events")
         verify_event(self, e[0], expected_state=BFDState.down)
 
-    def execute_rogue_session_scenario(self, vpp_bfd_udp_session,
-                                       legitimate_test_session,
-                                       rogue_test_session,
-                                       rogue_bfd_values=None):
-        """ execute a rogue session interaction scenario
+    def execute_rogue_session_scenario(
+        self,
+        vpp_bfd_udp_session,
+        legitimate_test_session,
+        rogue_test_session,
+        rogue_bfd_values=None,
+    ):
+        """execute a rogue session interaction scenario
 
         1. create vpp session, add config
         2. bring the legitimate session up
@@ -2178,7 +2359,8 @@ class BFDSHA1TestCase(VppTestCase):
             detect_mult=self.test_session.detect_mult,
             diag=self.test_session.diag,
             state=self.test_session.state,
-            auth_type=self.test_session.auth_type)
+            auth_type=self.test_session.auth_type,
+        )
         if rogue_bfd_values:
             rogue_test_session.update(**rogue_bfd_values)
         rogue_test_session.update(state=BFDState.down)
@@ -2187,69 +2369,84 @@ class BFDSHA1TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_mismatch_auth(self):
-        """ session is not brought down by unauthenticated msg """
+        """session is not brought down by unauthenticated msg"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         legitimate_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         rogue_test_session = BFDTestSession(self, self.pg0, AF_INET)
-        self.execute_rogue_session_scenario(vpp_session,
-                                            legitimate_test_session,
-                                            rogue_test_session)
+        self.execute_rogue_session_scenario(
+            vpp_session, legitimate_test_session, rogue_test_session
+        )
 
     def test_mismatch_bfd_key_id(self):
-        """ session is not brought down by msg with non-existent key-id """
+        """session is not brought down by msg with non-existent key-id"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         # pick a different random bfd key id
         x = randint(0, 255)
         while x == vpp_session.bfd_key_id:
             x = randint(0, 255)
         legitimate_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         rogue_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=x)
-        self.execute_rogue_session_scenario(vpp_session,
-                                            legitimate_test_session,
-                                            rogue_test_session)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=x
+        )
+        self.execute_rogue_session_scenario(
+            vpp_session, legitimate_test_session, rogue_test_session
+        )
 
     def test_mismatched_auth_type(self):
-        """ session is not brought down by msg with wrong auth type """
+        """session is not brought down by msg with wrong auth type"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         legitimate_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         rogue_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         self.execute_rogue_session_scenario(
-            vpp_session, legitimate_test_session, rogue_test_session,
-            {'auth_type': BFDAuthType.keyed_md5})
+            vpp_session,
+            legitimate_test_session,
+            rogue_test_session,
+            {"auth_type": BFDAuthType.keyed_md5},
+        )
 
     def test_restart(self):
-        """ simulate remote peer restart and resynchronization """
-        key = self.factory.create_random_key(
-            self, BFDAuthType.meticulous_keyed_sha1)
+        """simulate remote peer restart and resynchronization"""
+        key = self.factory.create_random_key(self, BFDAuthType.meticulous_keyed_sha1)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id, our_seq_number=0)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+            our_seq_number=0,
+        )
         bfd_session_up(self)
         # don't send any packets for 2*detection_time
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         self.sleep(2 * detection_time, "simulating peer restart")
         events = self.vapi.collect_events()
         self.assert_equal(len(events), 1, "number of bfd events")
@@ -2266,7 +2463,7 @@ class BFDSHA1TestCase(VppTestCase):
 
 @tag_run_solo
 class BFDAuthOnOffTestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (changing auth) """
+    """Bidirectional Forwarding Detection (BFD) (changing auth)"""
 
     pg0 = None
     vpp_session = None
@@ -2303,11 +2500,10 @@ class BFDAuthOnOffTestCase(VppTestCase):
         super(BFDAuthOnOffTestCase, self).tearDown()
 
     def test_auth_on_immediate(self):
-        """ turn auth on without disturbing session state (immediate) """
+        """turn auth on without disturbing session state (immediate)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4)
+        self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(self, self.pg0, AF_INET)
         bfd_session_up(self)
@@ -2323,19 +2519,23 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_off_immediate(self):
-        """ turn auth off without disturbing session state (immediate) """
+        """turn auth off without disturbing session state (immediate)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         # self.vapi.want_bfd_events(enable_disable=0)
         for dummy in range(self.test_session.detect_mult * 2):
@@ -2352,21 +2552,25 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.test_session.inc_seq_num()
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_change_key_immediate(self):
-        """ change auth key without disturbing session state (immediate) """
+        """change auth key without disturbing session state (immediate)"""
         key1 = self.factory.create_random_key(self)
         key1.add_vpp_config()
         key2 = self.factory.create_random_key(self)
         key2.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key1)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key1
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key1,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key1,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             p = wait_for_bfd_packet(self)
@@ -2380,15 +2584,13 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_on_delayed(self):
-        """ turn auth on without disturbing session state (delayed) """
+        """turn auth on without disturbing session state (delayed)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4)
+        self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(self, self.pg0, AF_INET)
         bfd_session_up(self)
@@ -2408,19 +2610,23 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_off_delayed(self):
-        """ turn auth off without disturbing session state (delayed) """
+        """turn auth off without disturbing session state (delayed)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             p = wait_for_bfd_packet(self)
@@ -2439,22 +2645,26 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_change_key_delayed(self):
-        """ change auth key without disturbing session state (delayed) """
+        """change auth key without disturbing session state (delayed)"""
         key1 = self.factory.create_random_key(self)
         key1.add_vpp_config()
         key2 = self.factory.create_random_key(self)
         key2.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key1)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key1
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key1,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key1,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             p = wait_for_bfd_packet(self)
@@ -2473,13 +2683,13 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
 
 @tag_run_solo
 class BFDCLITestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (CLI) """
+    """Bidirectional Forwarding Detection (BFD) (CLI)"""
+
     pg0 = None
 
     @classmethod
@@ -2516,52 +2726,54 @@ class BFDCLITestCase(VppTestCase):
         super(BFDCLITestCase, self).tearDown()
 
     def cli_verify_no_response(self, cli):
-        """ execute a CLI, asserting that the response is empty """
-        self.assert_equal(self.vapi.cli(cli),
-                          "",
-                          "CLI command response")
+        """execute a CLI, asserting that the response is empty"""
+        self.assert_equal(self.vapi.cli(cli), "", "CLI command response")
 
     def cli_verify_response(self, cli, expected):
-        """ execute a CLI, asserting that the response matches expectation """
+        """execute a CLI, asserting that the response matches expectation"""
         try:
             reply = self.vapi.cli(cli)
         except CliFailedCommandError as cli_error:
             reply = str(cli_error)
-        self.assert_equal(reply.strip(),
-                          expected,
-                          "CLI command response")
+        self.assert_equal(reply.strip(), expected, "CLI command response")
 
     def test_show(self):
-        """ show commands """
+        """show commands"""
         k1 = self.factory.create_random_key(self)
         k1.add_vpp_config()
         k2 = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         k2.add_vpp_config()
         s1 = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         s1.add_vpp_config()
-        s2 = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6, af=AF_INET6,
-                              sha1_key=k2)
+        s2 = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=k2
+        )
         s2.add_vpp_config()
         self.logger.info(self.vapi.ppcli("show bfd keys"))
         self.logger.info(self.vapi.ppcli("show bfd sessions"))
         self.logger.info(self.vapi.ppcli("show bfd"))
 
     def test_set_del_sha1_key(self):
-        """ set/delete SHA1 auth key """
+        """set/delete SHA1 auth key"""
         k = self.factory.create_random_key(self)
         self.registry.register(k, self.logger)
         self.cli_verify_no_response(
-            "bfd key set conf-key-id %s type keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key)))
+            "bfd key set conf-key-id %s type keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key),
+            )
+        )
         self.assertTrue(k.query_vpp_config())
         self.vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=k)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=k
+        )
         self.vpp_session.add_vpp_config()
-        self.test_session = \
-            BFDTestSession(self, self.pg0, AF_INET, sha1_key=k,
-                           bfd_key_id=self.vpp_session.bfd_key_id)
+        self.test_session = BFDTestSession(
+            self, self.pg0, AF_INET, sha1_key=k, bfd_key_id=self.vpp_session.bfd_key_id
+        )
         self.vapi.want_bfd_events()
         bfd_session_up(self)
         bfd_session_down(self)
@@ -2569,37 +2781,43 @@ class BFDCLITestCase(VppTestCase):
         # is in-use
         k2 = self.factory.create_random_key(self)
         self.cli_verify_response(
-            "bfd key set conf-key-id %s type keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key)),
+            "bfd key set conf-key-id %s type keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key),
+            ),
             "bfd key set: `bfd_auth_set_key' API call failed, "
-            "rv=-103:BFD object in use")
+            "rv=-103:BFD object in use",
+        )
         # manipulating the session using old secret should still work
         bfd_session_up(self)
         bfd_session_down(self)
         self.vpp_session.remove_vpp_config()
-        self.cli_verify_no_response(
-            "bfd key del conf-key-id %s" % k.conf_key_id)
+        self.cli_verify_no_response("bfd key del conf-key-id %s" % k.conf_key_id)
         self.assertFalse(k.query_vpp_config())
 
     def test_set_del_meticulous_sha1_key(self):
-        """ set/delete meticulous SHA1 auth key """
+        """set/delete meticulous SHA1 auth key"""
         k = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         self.registry.register(k, self.logger)
         self.cli_verify_no_response(
-            "bfd key set conf-key-id %s type meticulous-keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key)))
+            "bfd key set conf-key-id %s type meticulous-keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key),
+            )
+        )
         self.assertTrue(k.query_vpp_config())
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip6, af=AF_INET6,
-                                            sha1_key=k)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=k
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
-        self.test_session = \
-            BFDTestSession(self, self.pg0, AF_INET6, sha1_key=k,
-                           bfd_key_id=self.vpp_session.bfd_key_id)
+        self.test_session = BFDTestSession(
+            self, self.pg0, AF_INET6, sha1_key=k, bfd_key_id=self.vpp_session.bfd_key_id
+        )
         self.vapi.want_bfd_events()
         bfd_session_up(self)
         bfd_session_down(self)
@@ -2607,299 +2825,409 @@ class BFDCLITestCase(VppTestCase):
         # is in-use
         k2 = self.factory.create_random_key(self)
         self.cli_verify_response(
-            "bfd key set conf-key-id %s type keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key)),
+            "bfd key set conf-key-id %s type keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key),
+            ),
             "bfd key set: `bfd_auth_set_key' API call failed, "
-            "rv=-103:BFD object in use")
+            "rv=-103:BFD object in use",
+        )
         # manipulating the session using old secret should still work
         bfd_session_up(self)
         bfd_session_down(self)
         self.vpp_session.remove_vpp_config()
-        self.cli_verify_no_response(
-            "bfd key del conf-key-id %s" % k.conf_key_id)
+        self.cli_verify_no_response("bfd key del conf-key-id %s" % k.conf_key_id)
         self.assertFalse(k.query_vpp_config())
 
     def test_add_mod_del_bfd_udp(self):
-        """ create/modify/delete IPv4 BFD UDP session """
-        vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4)
+        """create/modify/delete IPv4 BFD UDP session"""
+        vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s" % (self.pg0.name, self.pg0.local_ip4,
-                                self.pg0.remote_ip4,
-                                vpp_session.desired_min_tx,
-                                vpp_session.required_min_rx,
-                                vpp_session.detect_mult)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4,
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-             mod_session.desired_min_tx, mod_session.required_min_rx,
-             mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
-            cli_del_cmd, "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            cli_del_cmd,
+            "bfd udp session del: `bfd_udp_del_session' API call"
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_add_mod_del_bfd_udp6(self):
-        """ create/modify/delete IPv6 BFD UDP session """
-        vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
+        """create/modify/delete IPv6 BFD UDP session"""
+        vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s" % (self.pg0.name, self.pg0.local_ip6,
-                                self.pg0.remote_ip6,
-                                vpp_session.desired_min_tx,
-                                vpp_session.required_min_rx,
-                                vpp_session.detect_mult)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6,
+            self,
+            self.pg0,
+            self.pg0.remote_ip6,
+            af=AF_INET6,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6,
-             mod_session.desired_min_tx,
-             mod_session.required_min_rx, mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip6, self.pg0.remote_ip6)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
             cli_del_cmd,
             "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_add_mod_del_bfd_udp_auth(self):
-        """ create/modify/delete IPv4 BFD UDP session (authenticated) """
+        """create/modify/delete IPv4 BFD UDP session (authenticated)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s conf-key-id %s bfd-key-id %s"\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-               vpp_session.desired_min_tx, vpp_session.required_min_rx,
-               vpp_session.detect_mult, key.conf_key_id,
-               vpp_session.bfd_key_id)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s conf-key-id %s bfd-key-id %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+                key.conf_key_id,
+                vpp_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key,
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            sha1_key=key,
             bfd_key_id=vpp_session.bfd_key_id,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-             mod_session.desired_min_tx,
-             mod_session.required_min_rx, mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
             cli_del_cmd,
             "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_add_mod_del_bfd_udp6_auth(self):
-        """ create/modify/delete IPv6 BFD UDP session (authenticated) """
+        """create/modify/delete IPv6 BFD UDP session (authenticated)"""
         key = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=key
+        )
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s conf-key-id %s bfd-key-id %s" \
-            % (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6,
-               vpp_session.desired_min_tx, vpp_session.required_min_rx,
-               vpp_session.detect_mult, key.conf_key_id,
-               vpp_session.bfd_key_id)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s conf-key-id %s bfd-key-id %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+                key.conf_key_id,
+                vpp_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=key,
+            self,
+            self.pg0,
+            self.pg0.remote_ip6,
+            af=AF_INET6,
+            sha1_key=key,
             bfd_key_id=vpp_session.bfd_key_id,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6,
-             mod_session.desired_min_tx,
-             mod_session.required_min_rx, mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip6, self.pg0.remote_ip6)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
             cli_del_cmd,
             "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_auth_on_off(self):
-        """ turn authentication on and off """
+        """turn authentication on and off"""
         key = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
-        auth_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                        sha1_key=key)
+        auth_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         session.add_vpp_config()
-        cli_activate = \
-            "bfd udp session auth activate interface %s local-addr %s "\
-            "peer-addr %s conf-key-id %s bfd-key-id %s"\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-               key.conf_key_id, auth_session.bfd_key_id)
+        cli_activate = (
+            "bfd udp session auth activate interface %s local-addr %s "
+            "peer-addr %s conf-key-id %s bfd-key-id %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                key.conf_key_id,
+                auth_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
-        cli_deactivate = \
-            "bfd udp session auth deactivate interface %s local-addr %s "\
-            "peer-addr %s "\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_deactivate = (
+            "bfd udp session auth deactivate interface %s local-addr %s "
+            "peer-addr %s " % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
 
     def test_auth_on_off_delayed(self):
-        """ turn authentication on and off (delayed) """
+        """turn authentication on and off (delayed)"""
         key = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
-        auth_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                        sha1_key=key)
+        auth_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         session.add_vpp_config()
-        cli_activate = \
-            "bfd udp session auth activate interface %s local-addr %s "\
-            "peer-addr %s conf-key-id %s bfd-key-id %s delayed yes"\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-               key.conf_key_id, auth_session.bfd_key_id)
+        cli_activate = (
+            "bfd udp session auth activate interface %s local-addr %s "
+            "peer-addr %s conf-key-id %s bfd-key-id %s delayed yes"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                key.conf_key_id,
+                auth_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
-        cli_deactivate = \
-            "bfd udp session auth deactivate interface %s local-addr %s "\
-            "peer-addr %s delayed yes"\
+        cli_deactivate = (
+            "bfd udp session auth deactivate interface %s local-addr %s "
+            "peer-addr %s delayed yes"
             % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
 
     def test_admin_up_down(self):
-        """ put session admin-up and admin-down """
+        """put session admin-up and admin-down"""
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         session.add_vpp_config()
-        cli_down = \
-            "bfd udp session set-flags admin down interface %s local-addr %s "\
-            "peer-addr %s "\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
-        cli_up = \
-            "bfd udp session set-flags admin up interface %s local-addr %s "\
-            "peer-addr %s "\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_down = (
+            "bfd udp session set-flags admin down interface %s local-addr %s "
+            "peer-addr %s " % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
+        cli_up = (
+            "bfd udp session set-flags admin up interface %s local-addr %s "
+            "peer-addr %s " % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_down)
         verify_bfd_session_config(self, session, state=BFDState.admin_down)
         self.cli_verify_no_response(cli_up)
         verify_bfd_session_config(self, session, state=BFDState.down)
 
     def test_set_del_udp_echo_source(self):
-        """ set/del udp echo source """
+        """set/del udp echo source"""
         self.create_loopback_interfaces(1)
         self.loopback0 = self.lo_interfaces[0]
         self.loopback0.admin_up()
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is not set.")
+        self.cli_verify_response("show bfd echo-source", "UDP echo source is not set.")
         cli_set = "bfd udp echo-source set interface %s" % self.loopback0.name
         self.cli_verify_no_response(cli_set)
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is: %s\n"
-                                 "IPv4 address usable as echo source: none\n"
-                                 "IPv6 address usable as echo source: none" %
-                                 self.loopback0.name)
+        self.cli_verify_response(
+            "show bfd echo-source",
+            "UDP echo source is: %s\n"
+            "IPv4 address usable as echo source: none\n"
+            "IPv6 address usable as echo source: none" % self.loopback0.name,
+        )
         self.loopback0.config_ip4()
-        echo_ip4 = str(ipaddress.IPv4Address(int(ipaddress.IPv4Address(
-            self.loopback0.local_ip4)) ^ 1))
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is: %s\n"
-                                 "IPv4 address usable as echo source: %s\n"
-                                 "IPv6 address usable as echo source: none" %
-                                 (self.loopback0.name, echo_ip4))
-        echo_ip6 = str(ipaddress.IPv6Address(int(ipaddress.IPv6Address(
-            self.loopback0.local_ip6)) ^ 1))
+        echo_ip4 = str(
+            ipaddress.IPv4Address(
+                int(ipaddress.IPv4Address(self.loopback0.local_ip4)) ^ 1
+            )
+        )
+        self.cli_verify_response(
+            "show bfd echo-source",
+            "UDP echo source is: %s\n"
+            "IPv4 address usable as echo source: %s\n"
+            "IPv6 address usable as echo source: none"
+            % (self.loopback0.name, echo_ip4),
+        )
+        echo_ip6 = str(
+            ipaddress.IPv6Address(
+                int(ipaddress.IPv6Address(self.loopback0.local_ip6)) ^ 1
+            )
+        )
         self.loopback0.config_ip6()
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is: %s\n"
-                                 "IPv4 address usable as echo source: %s\n"
-                                 "IPv6 address usable as echo source: %s" %
-                                 (self.loopback0.name, echo_ip4, echo_ip6))
+        self.cli_verify_response(
+            "show bfd echo-source",
+            "UDP echo source is: %s\n"
+            "IPv4 address usable as echo source: %s\n"
+            "IPv6 address usable as echo source: %s"
+            % (self.loopback0.name, echo_ip4, echo_ip6),
+        )
         cli_del = "bfd udp echo-source del"
         self.cli_verify_no_response(cli_del)
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is not set.")
+        self.cli_verify_response("show bfd echo-source", "UDP echo source is not set.")
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main(testRunner=VppTestRunner)