aboutsummaryrefslogtreecommitdiffstats
path: root/test/framework.py
blob: 7d03eebef9a309f29a4cb57fb182a6e8b573caf7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
#!/usr/bin/env python3

from __future__ import print_function
import gc
import logging
import sys
import os
import select
import signal
import subprocess
import unittest
import re
import time
import faulthandler
import random
import copy
import platform
import shutil
from collections import deque
from threading import Thread, Event
from inspect import getdoc, isclass
from traceback import format_exception
from logging import FileHandler, DEBUG, Formatter
from enum import Enum
from abc import ABC, abstractmethod
from struct import pack, unpack

import scapy.compat
from scapy.packet import Raw, Packet
from config import config, available_cpus, num_cpus, max_vpp_cpus
import hook as hookmodule
from vpp_pg_interface import VppPGInterface
from vpp_sub_interface import VppSubInterface
from vpp_lo_interface import VppLoInterface
from vpp_bvi_interface import VppBviInterface
from vpp_papi_provider import VppPapiProvider
from vpp_papi import VppEnum
import vpp_papi
from vpp_papi.vpp_stats import VPPStats
from vpp_papi.vpp_transport_socket import VppTransportSocketIOError
from log import RED, GREEN, YELLOW, double_line_delim, single_line_delim, \
    get_logger, colorize
from vpp_object import VppObjectRegistry
from util import ppp, is_core_present
from scapy.layers.inet import IPerror, TCPerror, UDPerror, ICMPerror
from scapy.layers.inet6 import ICMPv6DestUnreach, ICMPv6EchoRequest
from scapy.layers.inet6 import ICMPv6EchoReply


logger = logging.getLogger(__name__)

# Set up an empty logger for the testcase that can be overridden as necessary
null_logger = logging.getLogger('VppTestCase')
null_logger.addHandler(logging.NullHandler())

PASS = 0
FAIL = 1
ERROR = 2
SKIP = 3
TEST_RUN = 4
SKIP_CPU_SHORTAGE = 5


if config.debug_framework:
    import debug_internal

"""
  Test framework module.

  The module provides a set of tools for constructing and running tests and
  representing the results.
"""


class VppDiedError(Exception):
    """ exception for reporting that the subprocess has died."""

    signals_by_value = {v: k for k, v in signal.__dict__.items() if
                        k.startswith('SIG') and not k.startswith('SIG_')}

    def __init__(self, rv=None, testcase=None, method_name=None):
        self.rv = rv
        self.signal_name = None
        self.testcase = testcase
        self.method_name = method_name

        try:
            self.signal_name = VppDiedError.signals_by_value[-rv]
        except (KeyError, TypeError):
            pass

        if testcase is None and method_name is None:
            in_msg = ''
        else:
            in_msg = ' while running %s.%s' % (testcase, method_name)

        if self.rv:
            msg = "VPP subprocess died unexpectedly%s with return code: %d%s."\
                % (in_msg, self.rv, ' [%s]' %
                   (self.signal_name if
                    self.signal_name is not None else ''))
        else:
            msg = "VPP subprocess died unexpectedly%s." % in_msg

        super(VppDiedError, self).__init__(msg)


class _PacketInfo(object):
    """Private class to create packet info object.

    Help process information about the next packet.
    Set variables to default values.
    """
    #: Store the index of the packet.
    index = -1
    #: Store the index of the source packet generator interface of the packet.
    src = -1
    #: Store the index of the destination packet generator interface
    #: of the packet.
    dst = -1
    #: Store expected ip version
    ip = -1
    #: Store expected upper protocol
    proto = -1
    #: Store the copy of the former packet.
    data = None

    def __eq__(self, other):
        index = self.index == other.index
        src = self.src == other.src
        dst = self.dst == other.dst
        data = self.data == other.data
        return index and src and dst and data


def pump_output(testclass):
    """ pump output from vpp stdout/stderr to proper queues """
    stdout_fragment = ""
    stderr_fragment = ""
    while not testclass.pump_thread_stop_flag.is_set():
        readable = select.select([testclass.vpp.stdout.fileno(),
                                  testclass.vpp.stderr.fileno(),
                                  testclass.pump_thread_wakeup_pipe[0]],
                                 [], [])[0]
        if testclass.vpp.stdout.fileno() in readable:
            read = os.read(testclass.vpp.stdout.fileno(), 102400)
            if len(read) > 0:
                split = read.decode('ascii',
                                    errors='backslashreplace').splitlines(True)
                if len(stdout_fragment) > 0:
                    split[0] = "%s%s" % (stdout_fragment, split[0])
                if len(split) > 0 and split[-1].endswith("\n"):
                    limit = None
                else:
                    limit = -1
                    stdout_fragment = split[-1]
                testclass.vpp_stdout_deque.extend(split[:limit])
                if not config.cache_vpp_output:
                    for line in split[:limit]:
                        testclass.logger.info(
                            "VPP STDOUT: %s" % line.rstrip("\n"))
        if testclass.vpp.stderr.fileno() in readable:
            read = os.read(testclass.vpp.stderr.fileno(), 102400)
            if len(read) > 0:
                split = read.decode('ascii',
                                    errors='backslashreplace').splitlines(True)
                if len(stderr_fragment) > 0:
                    split[0] = "%s%s" % (stderr_fragment, split[0])
                if len(split) > 0 and split[-1].endswith("\n"):
                    limit = None
                else:
                    limit = -1
                    stderr_fragment = split[-1]

                testclass.vpp_stderr_deque.extend(split[:limit])
                if not config.cache_vpp_output:
                    for line in split[:limit]:
                        testclass.logger.error(
                            "VPP STDERR: %s" % line.rstrip("\n"))
                        # ignoring the dummy pipe here intentionally - the
                        # flag will take care of properly terminating the loop


def _is_platform_aarch64():
    return platform.machine() == 'aarch64'


is_platform_aarch64 = _is_platform_aarch64()


class KeepAliveReporter(object):
    """
    Singleton object which reports test start to parent process
    """
    _shared_state = {}

    def __init__(self):
        self.__dict__ = self._shared_state
        self._pipe = None

    @property
    def pipe(self):
        return self._pipe

    @pipe.setter
    def pipe(self, pipe):
        if self._pipe is not None:
            raise Exception("Internal error - pipe should only be set once.")
        self._pipe = pipe

    def send_keep_alive(self, test, desc=None):
        """
        Write current test tmpdir & desc to keep-alive pipe to signal liveness
        """
        if self.pipe is None:
            # if not running forked..
            return

        if isclass(test):
            desc = '%s (%s)' % (desc, unittest.util.strclass(test))
        else:
            desc = test.id()

        self.pipe.send((desc, config.vpp, test.tempdir, test.vpp.pid))


class TestCaseTag(Enum):
    # marks the suites that must run at the end
    # using only a single test runner
    RUN_SOLO = 1
    # marks the suites broken on VPP multi-worker
    FIXME_VPP_WORKERS = 2
    # marks the suites broken when ASan is enabled
    FIXME_ASAN = 3


def create_tag_decorator(e):
    def decorator(cls):
        try:
            cls.test_tags.append(e)
        except AttributeError:
            cls.test_tags = [e]
        return cls
    return decorator


tag_run_solo = create_tag_decorator(TestCaseTag.RUN_SOLO)
tag_fixme_vpp_workers = create_tag_decorator(TestCaseTag.FIXME_VPP_WORKERS)
tag_fixme_asan = create_tag_decorator(TestCaseTag.FIXME_ASAN)


class DummyVpp:
    returncode = None
    pid = 0xcafebafe

    def poll(self):
        pass

    def terminate(self):
        pass


class CPUInterface(ABC):
    cpus = []
    skipped_due_to_cpu_lack = False

    @classmethod
    @abstractmethod
    def get_cpus_required(cls):
        pass

    @classmethod
    def assign_cpus(cls, cpus):
        cls.cpus = cpus


class VppTestCase(CPUInterface, unittest.TestCase):
    """This subclass is a base class for VPP test cases that are implemented as
    classes. It provides methods to create and run test case.
    """

    extra_vpp_statseg_config = ""
    extra_vpp_punt_config = []
    extra_vpp_plugin_config = []
    logger = null_logger
    vapi_response_timeout = 5

    @property
    def packet_infos(self):
        """List of packet infos"""
        return self._packet_infos

    @classmethod
    def get_packet_count_for_if_idx(cls, dst_if_index):
        """Get the number of packet info for specified destination if index"""
        if dst_if_index in cls._packet_count_for_dst_if_idx:
            return cls._packet_count_for_dst_if_idx[dst_if_index]
        else:
            return 0

    @classmethod
    def has_tag(cls, tag):
        """ if the test case has a given tag - return true """
        try:
            return tag in cls.test_tags
        except AttributeError:
            pass
        return False

    @classmethod
    def is_tagged_run_solo(cls):
        """ if the test case class is timing-sensitive - return true """
        return cls.has_tag(TestCaseTag.RUN_SOLO)

    @classmethod
    def skip_fixme_asan(cls):
        """ if @tag_fixme_asan & ASan is enabled - mark for skip """
        if cls.has_tag(TestCaseTag.FIXME_ASAN):
            vpp_extra_cmake_args = os.environ.get('VPP_EXTRA_CMAKE_ARGS', '')
            if 'DVPP_ENABLE_SANITIZE_ADDR=ON' in vpp_extra_cmake_args:
                cls = unittest.skip("Skipping @tag_fixme_asan tests")(cls)

    @classmethod
    def instance(cls):
        """Return the instance of this testcase"""
        return cls.test_instance

    @classmethod
    def set_debug_flags(cls, d):
        cls.gdbserver_port = 7777
        cls.debug_core = False
        cls.debug_gdb = False
        cls.debug_gdbserver = False
        cls.debug_all = False
        cls.debug_attach = False
        if d is None:
            return
        dl = d.lower()
        if dl == "core":
            cls.debug_core = True
        elif dl == "gdb" or dl == "gdb-all":
            cls.debug_gdb = True
        elif dl == "gdbserver" or dl == "gdbserver-all":
            cls.debug_gdbserver = True
        elif dl == "attach":
            cls.debug_attach = True
        else:
            raise Exception("Unrecognized DEBUG option: '%s'" % d)
        if dl == "gdb-all" or dl == "gdbserver-all":
            cls.debug_all = True

    @classmethod
    def get_vpp_worker_count(cls):
        if not hasattr(cls, "vpp_worker_count"):
            if cls.has_tag(TestCaseTag.FIXME_VPP_WORKERS):
                cls.vpp_worker_count = 0
            else:
                cls.vpp_worker_count = config.vpp_worker_count
        return cls.vpp_worker_count

    @classmethod
    def get_cpus_required(cls):
        return 1 + cls.get_vpp_worker_count()

    @classmethod
    def setUpConstants(cls):
        """ Set-up the test case class based on environment variables """
        cls.step = config.step
        cls.plugin_path = ":".join(config.vpp_plugin_dir)
        cls.test_plugin_path = ":".join(config.vpp_test_plugin_dir)
        cls.extern_plugin_path = ":".join(config.extern_plugin_dir)
        debug_cli = ""
        if cls.step or cls.debug_gdb or cls.debug_gdbserver:
            debug_cli = "cli-listen localhost:5002"
        size = re.search(r"\d+[gG]", config.coredump_size)
        if size:
            coredump_size = f"coredump-size {config.coredump_size}".lower()
        else:
            coredump_size = "coredump-size unlimited"
        default_variant = config.variant
        if default_variant is not None:
            default_variant = "defaults { %s 100 }" % default_variant
        else:
            default_variant = ""

        api_fuzzing = config.api_fuzz
        if api_fuzzing is None:
            api_fuzzing = 'off'

        cls.vpp_cmdline = [
            config.vpp,
            "unix", "{", "nodaemon", debug_cli, "full-coredump",
            coredump_size, "runtime-dir", cls.tempdir, "}",
            "api-trace", "{", "on", "}",
            "api-segment", "{", "prefix", cls.get_api_segment_prefix(), "}",
            "cpu", "{", "main-core", str(cls.cpus[0]), ]
        if cls.extern_plugin_path not in (None, ""):
            cls.extra_vpp_plugin_config.append(
                "add-path %s" % cls.extern_plugin_path)
        if cls.get_vpp_worker_count():
            cls.vpp_cmdline.extend([
                "corelist-workers", ",".join([str(x) for x in cls.cpus[1:]])])
        cls.vpp_cmdline.extend([
            "}",
            "physmem", "{", "max-size", "32m", "}",
            "statseg", "{", "socket-name", cls.get_stats_sock_path(),
            cls.extra_vpp_statseg_config, "}",
            "socksvr", "{", "socket-name", cls.get_api_sock_path(), "}",
            "node { ", default_variant, "}",
            "api-fuzz {", api_fuzzing, "}",
            "plugins", "{", "plugin", "dpdk_plugin.so", "{", "disable", "}",
            "plugin", "rdma_plugin.so", "{", "disable", "}",
            "plugin", "lisp_unittest_plugin.so", "{", "enable", "}",
            "plugin", "unittest_plugin.so", "{", "enable", "}"
        ] + cls.extra_vpp_plugin_config + ["}", ])

        if cls.extra_vpp_punt_config is not None:
            cls.vpp_cmdline.extend(cls.extra_vpp_punt_config)

        if not cls.debug_attach:
            cls.logger.info("vpp_cmdline args: %s" % cls.vpp_cmdline)
            cls.logger.info("vpp_cmdline: %s" % " ".join(cls.vpp_cmdline))

    @classmethod
    def wait_for_enter(cls):
        if cls.debug_gdbserver:
            print(double_line_delim)
            print("Spawned GDB server with PID: %d" % cls.vpp.pid)
        elif cls.debug_gdb:
            print(double_line_delim)
            print("Spawned VPP with PID: %d" % cls.vpp.pid)
        else:
            cls.logger.debug("Spawned VPP with PID: %d" % cls.vpp.pid)
            return
        print(single_line_delim)
        print("You can debug VPP using:")
        if cls.debug_gdbserver:
            print(f"sudo gdb {config.vpp} "
                  f"-ex 'target remote localhost:{cls.gdbserver_port}'")
            print("Now is the time to attach gdb by running the above "
                  "command, set up breakpoints etc., then resume VPP from "
                  "within gdb by issuing the 'continue' command")
            cls.gdbserver_port += 1
        elif cls.debug_gdb:
            print(f"sudo gdb {config.vpp} -ex 'attach {cls.vpp.pid}'")
            print("Now is the time to attach gdb by running the above "
                  "command and set up breakpoints etc., then resume VPP from"
                  " within gdb by issuing the 'continue' command")
        print(single_line_delim)
        input("Press ENTER to continue running the testcase...")

    @classmethod
    def attach_vpp(cls):
        cls.vpp = DummyVpp()

    @classmethod
    def run_vpp(cls):
        cls.logger.debug(f"Assigned cpus: {cls.cpus}")
        cmdline = cls.vpp_cmdline

        if cls.debug_gdbserver:
            gdbserver = '/usr/bin/gdbserver'
            if not os.path.isfile(gdbserver) or\
                    not os.access(gdbserver, os.X_OK):
                raise Exception("gdbserver binary '%s' does not exist or is "
                                "not executable" % gdbserver)

            cmdline = [gdbserver, 'localhost:{port}'
                       .format(port=cls.gdbserver_port)] + cls.vpp_cmdline
            cls.logger.info("Gdbserver cmdline is %s", " ".join(cmdline))

        try:
            cls.vpp = subprocess.Popen(cmdline,
                                       stdout=subprocess.PIPE,
                                       stderr=subprocess.PIPE)
        except subprocess.CalledProcessError as e:
            cls.logger.critical("Subprocess returned with non-0 return code: ("
                                "%s)", e.returncode)
            raise
        except OSError as e:
            cls.logger.critical("Subprocess returned with OS error: "
                                "(%s) %s", e.errno, e.strerror)
            raise
        except Exception as e:
            cls.logger.exception("Subprocess returned unexpected from "
                                 "%s:", cmdline)
            raise

        cls.wait_for_enter()

    @classmethod
    def wait_for_coredump(cls):
        corefile = cls.tempdir + "/core"
        if os.path.isfile(corefile):
            cls.logger.error("Waiting for coredump to complete: %s", corefile)
            curr_size = os.path.getsize(corefile)
            deadline = time.time() + 60
            ok = False
            while time.time() < deadline:
                cls.sleep(1)
                size = curr_size
                curr_size = os.path.getsize(corefile)
                if size == curr_size:
                    ok = True
                    break
            if not ok:
                cls.logger.error("Timed out waiting for coredump to complete:"
                                 " %s", corefile)
            else:
                cls.logger.error("Coredump complete: %s, size %d",
                                 corefile, curr_size)

    @classmethod
    def get_stats_sock_path(cls):
        return "%s/stats.sock" % cls.tempdir

    @classmethod
    def get_api_sock_path(cls):
        return "%s/api.sock" % cls.tempdir

    @classmethod
    def get_api_segment_prefix(cls):
        return os.path.basename(cls.tempdir)  # Only used for VAPI

    @classmethod
    def get_tempdir(cls):
        tmpdir = f"{config.tmp_dir}/vpp-unittest-{cls.__name__}"
        if config.wipe_tmp_dir:
            shutil.rmtree(tmpdir, ignore_errors=True)
        os.mkdir(tmpdir)
        return tmpdir

    @classmethod
    def create_file_handler(cls):
        if config.log_dir is None:
            cls.file_handler = FileHandler(f"{cls.tempdir}/log.txt")
            return

        logdir = f"{config.log_dir}/vpp-unittest-{cls.__name__}"
        if config.wipe_tmp_dir:
            shutil.rmtree(logdir, ignore_errors=True)
        os.mkdir(logdir)
        cls.file_handler = FileHandler(f"{logdir}/log.txt")

    @classmethod
    def setUpClass(cls):
        """
        Perform class setup before running the testcase
        Remove shared memory files, start vpp and connect the vpp-api
        """
        super(VppTestCase, cls).setUpClass()
        cls.logger = get_logger(cls.__name__)
        random.seed(config.rnd_seed)
        if hasattr(cls, 'parallel_handler'):
            cls.logger.addHandler(cls.parallel_handler)
            cls.logger.propagate = False
        cls.set_debug_flags(config.debug)
        cls.tempdir = cls.get_tempdir()
        cls.create_file_handler()
        cls.file_handler.setFormatter(
            Formatter(fmt='%(asctime)s,%(msecs)03d %(message)s',
                      datefmt="%H:%M:%S"))
        cls.file_handler.setLevel(DEBUG)
        cls.logger.addHandler(cls.file_handler)
        cls.logger.debug("--- setUpClass() for %s called ---" % cls.__name__)
        os.chdir(cls.tempdir)
        cls.logger.info("Temporary dir is %s, api socket is %s",
                        cls.tempdir, cls.get_api_sock_path())
        cls.logger.debug("Random seed is %s", config.rnd_seed)
        cls.setUpConstants()
        cls.reset_packet_infos()
        cls._pcaps = []
        cls._old_pcaps = []
        cls.verbose = 0
        cls.vpp_dead = False
        cls.registry = VppObjectRegistry()
        cls.vpp_startup_failed = False
        cls.reporter = KeepAliveReporter()
        # need to catch exceptions here because if we raise, then the cleanup
        # doesn't get called and we might end with a zombie vpp
        try:
            if cls.debug_attach:
                cls.attach_vpp()
            else:
                cls.run_vpp()
            cls.reporter.send_keep_alive(cls, 'setUpClass')
            VppTestResult.current_test_case_info = TestCaseInfo(
                cls.logger, cls.tempdir, cls.vpp.pid, config.vpp)
            cls.vpp_stdout_deque = deque()
            cls.vpp_stderr_deque = deque()
            if not cls.debug_attach:
                cls.pump_thread_stop_flag = Event()
                cls.pump_thread_wakeup_pipe = os.pipe()
                cls.pump_thread = Thread(target=pump_output, args=(cls,))
                cls.pump_thread.daemon = True
                cls.pump_thread.start()
            if cls.debug_gdb or cls.debug_gdbserver or cls.debug_attach:
                cls.vapi_response_timeout = 0
            cls.vapi = VppPapiProvider(cls.__name__, cls,
                                       cls.vapi_response_timeout)
            if cls.step:
                hook = hookmodule.StepHook(cls)
            else:
                hook = hookmodule.PollHook(cls)
            cls.vapi.register_hook(hook)
            cls.statistics = VPPStats(socketname=cls.get_stats_sock_path())
            try:
                hook.poll_vpp()
            except VppDiedError:
                cls.vpp_startup_failed = True
                cls.logger.critical(
                    "VPP died shortly after startup, check the"
                    " output to standard error for possible cause")
                raise
            try:
                cls.vapi.connect()
            except (vpp_papi.VPPIOError, Exception) as e:
                cls.logger.debug("Exception connecting to vapi: %s" % e)
                cls.vapi.disconnect()

                if cls.debug_gdbserver:
                    print(colorize("You're running VPP inside gdbserver but "
                                   "VPP-API connection failed, did you forget "
                                   "to 'continue' VPP from within gdb?", RED))
                raise e
            if cls.debug_attach:
                last_line = cls.vapi.cli("show thread").split("\n")[-2]
                cls.vpp_worker_count = int(last_line.split(" ")[0])
                print("Detected VPP with %s workers." % cls.vpp_worker_count)
        except vpp_papi.VPPRuntimeError as e:
            cls.logger.debug("%s" % e)
            cls.quit()
            raise e
        except Exception as e:
            cls.logger.debug("Exception connecting to VPP: %s" % e)
            cls.quit()
            raise e

    @classmethod
    def _debug_quit(cls):
        if (cls.debug_gdbserver or cls.debug_gdb):
            try:
                cls.vpp.poll()

                if cls.vpp.returncode is None:
                    print()
                    print(double_line_delim)
                    print("VPP or GDB server is still running")
                    print(single_line_delim)
                    input("When done debugging, press ENTER to kill the "
                          "process and finish running the testcase...")
            except AttributeError:
                pass

    @classmethod
    def quit(cls):
        """
        Disconnect vpp-api, kill vpp and cleanup shared memory files
        """
        cls._debug_quit()

        # first signal that we want to stop the pump thread, then wake it up
        if hasattr(cls, 'pump_thread_stop_flag'):
            cls.pump_thread_stop_flag.set()
        if hasattr(cls, 'pump_thread_wakeup_pipe'):
            os.write(cls.pump_thread_wakeup_pipe[1], b'ding dong wake up')
        if hasattr(cls, 'pump_thread'):
            cls.logger.debug("Waiting for pump thread to stop")
            cls.pump_thread.join()
        if hasattr(cls, 'vpp_stderr_reader_thread'):
            cls.logger.debug("Waiting for stderr pump to stop")
            cls.vpp_stderr_reader_thread.join()

        if hasattr(cls, 'vpp'):
            if hasattr(cls, 'vapi'):
                cls.logger.debug(cls.vapi.vpp.get_stats())
                cls.logger.debug("Disconnecting class vapi client on %s",
                                 cls.__name__)
                cls.vapi.disconnect()
                cls.logger.debug("Deleting class vapi attribute on %s",
                                 cls.__name__)
                del cls.vapi
            cls.vpp.poll()
            if not cls.debug_attach and cls.vpp.returncode is None:
                cls.wait_for_coredump()
                cls.logger.debug("Sending TERM to vpp")
                cls.vpp.terminate()
                cls.logger.debug("Waiting for vpp to die")
                try:
                    outs, errs = cls.vpp.communicate(timeout=5)
                except subprocess.TimeoutExpired:
                    cls.vpp.kill()
                    outs, errs = cls.vpp.communicate()
            cls.logger.debug("Deleting class vpp attribute on %s",
                             cls.__name__)
            if not cls.debug_attach:
                cls.vpp.stdout.close()
                cls.vpp.stderr.close()
            del cls.vpp

        if cls.vpp_startup_failed:
            stdout_log = cls.logger.info
            stderr_log = cls.logger.critical
        else:
            stdout_log = cls.logger.info
            stderr_log = cls.logger.info

        if hasattr(cls, 'vpp_stdout_deque'):
            stdout_log(single_line_delim)
            stdout_log('VPP output to stdout while running %s:', cls.__name__)
            stdout_log(single_line_delim)
            vpp_output = "".join(cls.vpp_stdout_deque)
            with open(cls.tempdir + '/vpp_stdout.txt', 'w') as f:
                f.write(vpp_output)
            stdout_log('\n%s', vpp_output)
            stdout_log(single_line_delim)

        if hasattr(cls, 'vpp_stderr_deque'):
            stderr_log(single_line_delim)
            stderr_log('VPP output to stderr while running %s:', cls.__name__)
            stderr_log(single_line_delim)
            vpp_output = "".join(cls.vpp_stderr_deque)
            with open(cls.tempdir + '/vpp_stderr.txt', 'w') as f:
                f.write(vpp_output)
            stderr_log('\n%s', vpp_output)
            stderr_log(single_line_delim)

    @classmethod
    def tearDownClass(cls):
        """ Perform final cleanup after running all tests in this test-case """
        cls.logger.debug("--- tearDownClass() for %s called ---" %
                         cls.__name__)
        cls.reporter.send_keep_alive(cls, 'tearDownClass')
        cls.quit()
        cls.file_handler.close()
        cls.reset_packet_infos()
        if config.debug_framework:
            debug_internal.on_tear_down_class(cls)

    def show_commands_at_teardown(self):
        """ Allow subclass specific teardown logging additions."""
        self.logger.info("--- No test specific show commands provided. ---")

    def tearDown(self):
        """ Show various debug prints after each test """
        self.logger.debug("--- tearDown() for %s.%s(%s) called ---" %
                          (self.__class__.__name__, self._testMethodName,
                           self._testMethodDoc))

        try:
            if not self.vpp_dead:
                self.logger.debug(self.vapi.cli("show trace max 1000"))
                self.logger.info(self.vapi.ppcli("show interface"))
                self.logger.info(self.vapi.ppcli("show hardware"))
                self.logger.info(self.statistics.set_errors_str())
                self.logger.info(self.vapi.ppcli("show run"))
                self.logger.info(self.vapi.ppcli("show log"))
                self.logger.info(self.vapi.ppcli("show bihash"))
                self.logger.info("Logging testcase specific show commands.")
                self.show_commands_at_teardown()
                self.registry.remove_vpp_config(self.logger)
            # Save/Dump VPP api trace log
            m = self._testMethodName
            api_trace = "vpp_api_trace.%s.%d.log" % (m, self.vpp.pid)
            tmp_api_trace = "/tmp/%s" % api_trace
            vpp_api_trace_log = "%s/%s" % (self.tempdir, api_trace)
            self.logger.info(self.vapi.ppcli("api trace save %s" % api_trace))
            self.logger.info("Moving %s to %s\n" % (tmp_api_trace,
                                                    vpp_api_trace_log))
            os.rename(tmp_api_trace, vpp_api_trace_log)
        except VppTransportSocketIOError:
            self.logger.debug("VppTransportSocketIOError: Vpp dead. "
                              "Cannot log show commands.")
            self.vpp_dead = True
        else:
            self.registry.unregister_all(self.logger)

    def setUp(self):
        """ Clear trace before running each test"""
        super(VppTestCase, self).setUp()
        self.reporter.send_keep_alive(self)
        if self.vpp_dead:
            raise VppDiedError(rv=None, testcase=self.__class__.__name__,
                               method_name=self._testMethodName)
        self.sleep(.1, "during setUp")
        self.vpp_stdout_deque.append(
            "--- test setUp() for %s.%s(%s) starts here ---\n" %
            (self.__class__.__name__, self._testMethodName,
             self._testMethodDoc))
        self.vpp_stderr_deque.append(
            "--- test setUp() for %s.%s(%s) starts here ---\n" %
            (self.__class__.__name__, self._testMethodName,
             self._testMethodDoc))
        self.vapi.cli("clear trace")
        # store the test instance inside the test class - so that objects
        # holding the class can access instance methods (like assertEqual)
        type(self).test_instance = self

    @classmethod
    def pg_enable_capture(cls, interfaces=None):
        """
        Enable capture on packet-generator interfaces

        :param interfaces: iterable interface indexes (if None,
                           use self.pg_interfaces)

        """
        if interfaces is None:
            interfaces = cls.pg_interfaces
        for i in interfaces:
            i.enable_capture()

    @classmethod
    def register_pcap(cls, intf, worker):
        """ Register a pcap in the testclass """
        # add to the list of captures with current timestamp
        cls._pcaps.append((intf, worker))

    @classmethod
    def get_vpp_time(cls):
        # processes e.g. "Time now 2.190522, Wed, 11 Mar 2020 17:29:54 GMT"
        # returns float("2.190522")
        timestr = cls.vapi.cli('show clock')
        head, sep, tail = timestr.partition(',')
        head, sep, tail = head.partition('Time now')
        return float(tail)

    @classmethod
    def sleep_on_vpp_time(cls, sec):
        """ Sleep according to time in VPP world """
        # On a busy system with many processes
        # we might end up with VPP time being slower than real world
        # So take that into account when waiting for VPP to do something
        start_time = cls.get_vpp_time()
        while cls.get_vpp_time() - start_time < sec:
            cls.sleep(0.1)

    @classmethod
    def pg_start(cls, trace=True):
        """ Enable the PG, wait till it is done, then clean up """
        for (intf, worker) in cls._old_pcaps:
            intf.handle_old_pcap_file(intf.get_in_path(worker),
                                      intf.in_history_counter)
        cls._old_pcaps = []
        if trace:
            cls.vapi.cli("clear trace")
            cls.vapi.cli("trace add pg-input 1000")
        cls.vapi.cli('packet-generator enable')
        # PG, when starts, runs to completion -
        # so let's avoid a race condition,
        # and wait a little till it's done.
        # Then clean it up  - and then be gone.
        deadline = time.time() + 300
        while cls.vapi.cli('show packet-generator').find("Yes") != -1:
            cls.sleep(0.01)  # yield
            if time.time() > deadline:
                cls.logger.error("Timeout waiting for pg to stop")
                break
        for intf, worker in cls._pcaps:
            cls.vapi.cli('packet-generator delete %s' %
                         intf.get_cap_name(worker))
        cls._old_pcaps = cls._pcaps
        cls._pcaps = []

    @classmethod
    def create_pg_interfaces_internal(cls, interfaces, gso=0, gso_size=0,
                                      mode=None):
        """
        Create packet-generator interfaces.

        :param interfaces: iterable indexes of the interfaces.
        :returns: List of created interfaces.

        """
        result = []
        for i in interfaces:
            intf = VppPGInterface(cls, i, gso, gso_size, mode)
            setattr(cls, intf.name, intf)
            result.append(intf)
        cls.pg_interfaces = result
        return result

    @classmethod
    def create_pg_ip4_interfaces(cls, interfaces, gso=0, gso_size=0):
        pgmode = VppEnum.vl_api_pg_interface_mode_t
        return cls.create_pg_interfaces_internal(interfaces, gso, gso_size,
                                                 pgmode.PG_API_MODE_IP4)

    @classmethod
    def create_pg_ip6_interfaces(cls, interfaces, gso=0, gso_size=0):
        pgmode = VppEnum.vl_api_pg_interface_mode_t
        return cls.create_pg_interfaces_internal(interfaces, gso, gso_size,
                                                 pgmode.PG_API_MODE_IP6)

    @classmethod
    def create_pg_interfaces(cls, interfaces, gso=0, gso_size=0):
        pgmode = VppEnum.vl_api_pg_interface_mode_t
        return cls.create_pg_interfaces_internal(interfaces, gso, gso_size,
                                                 pgmode.PG_API_MODE_ETHERNET)

    @classmethod
    def create_pg_ethernet_interfaces(cls, interfaces, gso=0, gso_size=0):
        pgmode = VppEnum.vl_api_pg_interface_mode_t
        return cls.create_pg_interfaces_internal(interfaces, gso, gso_size,
                                                 pgmode.PG_API_MODE_ETHERNET)

    @classmethod
    def create_loopback_interfaces(cls, count):
        """
        Create loopback interfaces.

        :param count: number of interfaces created.
        :returns: List of created interfaces.
        """
        result = [VppLoInterface(cls) for i in range(count)]
        for intf in result:
            setattr(cls, intf.name, intf)
        cls.lo_interfaces = result
        return result

    @classmethod
    def create_bvi_interfaces(cls, count):
        """
        Create BVI interfaces.

        :param count: number of interfaces created.
        :returns: List of created interfaces.
        """
        result = [VppBviInterface(cls) for i in range(count)]
        for intf in result:
            setattr(cls, intf.name, intf)
        cls.bvi_interfaces = result
        return result

    @staticmethod
    def extend_packet(packet, size, padding=' '):
        """
        Extend packet to given size by padding with spaces or custom padding
        NOTE: Currently works only when Raw layer is present.

        :param packet: packet
        :param size: target size
        :param padding: padding used to extend the payload

        """
        packet_len = len(packet) + 4
        extend = size - packet_len
        if extend > 0:
            num = (extend // len(padding)) + 1
            packet[Raw].load += (padding * num)[:extend].encode("ascii")

    @classmethod
    def reset_packet_infos(cls):
        """ Reset the list of packet info objects and packet counts to zero """
        cls._packet_infos = {}
        cls._packet_count_for_dst_if_idx = {}

    @classmethod
    def create_packet_info(cls, src_if, dst_if):
        """
        Create packet info object containing the source and destination indexes
        and add it to the testcase's packet info list

        :param VppInterface src_if: source interface
        :param VppInterface dst_if: destination interface

        :returns: _PacketInfo object

        """
        info = _PacketInfo()
        info.index = len(cls._packet_infos)
        info.src = src_if.sw_if_index
        info.dst = dst_if.sw_if_index
        if isinstance(dst_if, VppSubInterface):
            dst_idx = dst_if.parent.sw_if_index
        else:
            dst_idx = dst_if.sw_if_index
        if dst_idx in cls._packet_count_for_dst_if_idx:
            cls._packet_count_for_dst_if_idx[dst_idx] += 1
        else:
            cls._packet_count_for_dst_if_idx[dst_idx] = 1
        cls._packet_infos[info.index] = info
        return info

    @staticmethod
    def info_to_payload(info):
        """
        Convert _PacketInfo object to packet payload

        :param info: _PacketInfo object

        :returns: string containing serialized data from packet info
        """

        # retrieve payload, currently 18 bytes (4 x ints + 1 short)
        return pack('iiiih', info.index, info.src,
                    info.dst, info.ip, info.proto)

    @staticmethod
    def payload_to_info(payload, payload_field='load'):
        """
        Convert packet payload to _PacketInfo object

        :param payload: packet payload
        :type payload:  <class 'scapy.packet.Raw'>
        :param payload_field: packet fieldname of payload "load" for
                <class 'scapy.packet.Raw'>
        :type payload_field: str
        :returns: _PacketInfo object containing de-serialized data from payload

        """

        # retrieve payload, currently 18 bytes (4 x ints + 1 short)
        payload_b = getattr(payload, payload_field)[:18]

        info = _PacketInfo()
        info.index, info.src, info.dst, info.ip, info.proto \
            = unpack('iiiih', payload_b)

        # some SRv6 TCs depend on get an exception if bad values are detected
        if info.index > 0x4000:
            raise ValueError('Index value is invalid')

        return info

    def get_next_packet_info(self, info):
        """
        Iterate over the packet info list stored in the testcase
        Start iteration with first element if info is None
        Continue based on index in info if info is specified

        :param info: info or None
        :returns: next info in list or None if no more infos
        """
        if info is None:
            next_index = 0
        else:
            next_index = info.index + 1
        if next_index == len(self._packet_infos):
            return None
        else:
            return self._packet_infos[next_index]

    def get_next_packet_info_for_interface(self, src_index, info):
        """
        Search the packet info list for the next packet info with same source
        interface index

        :param src_index: source interface index to search for
        :param info: packet info - where to start the search
        :returns: packet info or None

        """
        while True:
            info = self.get_next_packet_info(info)
            if info is None:
                return None
            if info.src == src_index:
                return info

    def get_next_packet_info_for_interface2(self, src_index, dst_index, info):
        """
        Search the packet info list for the next packet info with same source
        and destination interface indexes

        :param src_index: source interface index to search for
        :param dst_index: destination interface index to search for
        :param info: packet info - where to start the search
        :returns: packet info or None

        """
        while True:
            info = self.get_next_packet_info_for_interface(src_index, info)
            if info is None:
                return None
            if info.dst == dst_index:
                return info

    def assert_equal(self, real_value, expected_value, name_or_class=None):
        if name_or_class is None:
            self.assertEqual(real_value, expected_value)
            return
        try:
            msg = "Invalid %s: %d('%s') does not match expected value %d('%s')"
            msg = msg % (getdoc(name_or_class).strip(),
                         real_value, str(name_or_class(real_value)),
                         expected_value, str(name_or_class(expected_value)))
        except Exception:
            msg = "Invalid %s: %s does not match expected value %s" % (
                name_or_class, real_value, expected_value)

        self.assertEqual(real_value, expected_value, msg)

    def assert_in_range(self,
                        real_value,
                        expected_min,
                        expected_max,
                        name=None):
        if name is None:
            msg = None
        else:
            msg = "Invalid %s: %s out of range <%s,%s>" % (
                name, real_value, expected_min, expected_max)
        self.assertTrue(expected_min <= real_value <= expected_max, msg)

    def assert_packet_checksums_valid(self, packet,
                                      ignore_zero_udp_checksums=True):
        received = packet.__class__(scapy.compat.raw(packet))
        udp_layers = ['UDP', 'UDPerror']
        checksum_fields = ['cksum', 'chksum']
        checksums = []
        counter = 0
        temp = received.__class__(scapy.compat.raw(received))
        while True:
            layer = temp.getlayer(counter)
            if layer:
                layer = layer.copy()
                layer.remove_payload()
                for cf in checksum_fields:
                    if hasattr(layer, cf):
                        if ignore_zero_udp_checksums and \
                                0 == getattr(layer, cf) and \
                                layer.name in udp_layers:
                            continue
                        delattr(temp.getlayer(counter), cf)
                        checksums.append((counter, cf))
            else:
                break
            counter = counter + 1
        if 0 == len(checksums):
            return
        temp = temp.__class__(scapy.compat.raw(temp))
        for layer, cf in checksums:
            calc_sum = getattr(temp[layer], cf)
            self.assert_equal(
                getattr(received[layer], cf), calc_sum,
                "packet checksum on layer #%d: %s" % (layer, temp[layer].name))
            self.logger.debug(
                "Checksum field `%s` on `%s` layer has correct value `%s`" %
                (cf, temp[layer].name, calc_sum))

    def assert_checksum_valid(self, received_packet, layer,
                              field_name='chksum',
                              ignore_zero_checksum=False):
        """ Check checksum of received packet on given layer """
        received_packet_checksum = getattr(received_packet[layer], field_name)
        if ignore_zero_checksum and 0 == received_packet_checksum:
            return
        recalculated = received_packet.__class__(
            scapy.compat.raw(received_packet))
        delattr(recalculated[layer], field_name)
        recalculated = recalculated.__class__(scapy.compat.raw(recalculated))
        self.assert_equal(received_packet_checksum,
                          getattr(recalculated[layer], field_name),
                          "packet checksum on layer: %s" % layer)

    def assert_ip_checksum_valid(self, received_packet,
                                 ignore_zero_checksum=False):
        self.assert_checksum_valid(received_packet, 'IP',
                                   ignore_zero_checksum=ignore_zero_checksum)

    def assert_tcp_checksum_valid(self, received_packet,
                                  ignore_zero_checksum=False):
        self.assert_checksum_valid(received_packet, 'TCP',
                                   ignore_zero_checksum=ignore_zero_checksum)

    def assert_udp_checksum_valid(self, received_packet,
                                  ignore_zero_checksum=True):
        self.assert_checksum_valid(received_packet, 'UDP',
                                   ignore_zero_checksum=ignore_zero_checksum)

    def assert_embedded_icmp_checksum_valid(self, received_packet):
        if received_packet.haslayer(IPerror):
            self.assert_checksum_valid(received_packet, 'IPerror')
        if received_packet.haslayer(TCPerror):
            self.assert_checksum_valid(received_packet, 'TCPerror')
        if received_packet.haslayer(UDPerror):
            self.assert_checksum_valid(received_packet, 'UDPerror',
                                       ignore_zero_checksum=True)
        if received_packet.haslayer(ICMPerror):
            self.assert_checksum_valid(received_packet, 'ICMPerror')

    def assert_icmp_checksum_valid(self, received_packet):
        self.assert_checksum_valid(received_packet, 'ICMP')
        self.assert_embedded_icmp_checksum_valid(received_packet)

    def assert_icmpv6_checksum_valid(self, pkt):
        if pkt.haslayer(ICMPv6DestUnreach):
            self.assert_checksum_valid(pkt, 'ICMPv6DestUnreach', 'cksum')
            self.assert_embedded_icmp_checksum_valid(pkt)
        if pkt.haslayer(ICMPv6EchoRequest):
            self.assert_checksum_valid(pkt, 'ICMPv6EchoRequest', 'cksum')
        if pkt.haslayer(ICMPv6EchoReply):
            self.assert_checksum_valid(pkt, 'ICMPv6EchoReply', 'cksum')

    def get_packet_counter(self, counter):
        if counter.startswith("/"):
            counter_value = self.statistics.get_counter(counter)
        else:
            counters = self.vapi.cli("sh errors").split('\n')
            counter_value = 0
            for i in range(1, len(counters) - 1):
                results = counters[i].split()
                if results[1] == counter:
                    counter_value = int(results[0])
                    break
        return counter_value

    def assert_packet_counter_equal(self, counter, expected_value):
        counter_value = self.get_packet_counter(counter)
        self.assert_equal(counter_value, expected_value,
                          "packet counter `%s'" % counter)

    def assert_error_counter_equal(self, counter, expected_value):
        counter_value = self.statistics[counter].sum()
        self.assert_equal(counter_value, expected_value,
                          "error counter `%s'" % counter)

    @classmethod
    def sleep(cls, timeout, remark=None):

        # /* Allow sleep(0) to maintain win32 semantics, and as decreed
        #  * by Guido, only the main thread can be interrupted.
        # */
        # https://github.com/python/cpython/blob/6673decfa0fb078f60587f5cb5e98460eea137c2/Modules/timemodule.c#L1892  # noqa
        if timeout == 0:
            # yield quantum
            if hasattr(os, 'sched_yield'):
                os.sched_yield()
            else:
                time.sleep(0)
            return

        cls.logger.debug("Starting sleep for %es (%s)", timeout, remark)
        before = time.time()
        time.sleep(timeout)
        after = time.time()
        if after - before > 2 * timeout:
            cls.logger.error("unexpected self.sleep() result - "
                             "slept for %es instead of ~%es!",
                             after - before, timeout)

        cls.logger.debug(
            "Finished sleep (%s) - slept %es (wanted %es)",
            remark, after - before, timeout)

    def virtual_sleep(self, timeout, remark=None):
        self.logger.debug("Moving VPP time by %s (%s)", timeout, remark)
        self.vapi.cli("set clock adjust %s" % timeout)

    def pg_send(self, intf, pkts, worker=None, trace=True):
        intf.add_stream(pkts, worker=worker)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start(trace=trace)

    def send_and_assert_no_replies(self, intf, pkts, remark="", timeout=None,
                                   trace=True):
        self.pg_send(intf, pkts)
        if not timeout:
            timeout = 1
        for i in self.pg_interfaces:
            i.get_capture(0, timeout=timeout)
            i.assert_nothing_captured(remark=remark)
            timeout = 0.1
        if trace:
            self.logger.debug(self.vapi.cli("show trace"))

    def send_and_expect(self, intf, pkts, output, n_rx=None, worker=None,
                        trace=True):
        if not n_rx:
            n_rx = 1 if isinstance(pkts, Packet) else len(pkts)
        self.pg_send(intf, pkts, worker=worker, trace=trace)
        rx = output.get_capture(n_rx)
        if trace:
            self.logger.debug(self.vapi.cli("show trace"))
        return rx

    def send_and_expect_load_balancing(self, input, pkts, outputs,
                                       worker=None, trace=True):
        self.pg_send(input, pkts, worker=worker, trace=trace)
        rxs = []
        for oo in outputs:
            rx = oo._get_capture(1)
            self.assertNotEqual(0, len(rx))
            rxs.append(rx)
        if trace:
            self.logger.debug(self.vapi.cli("show trace"))
        return rxs

    def send_and_expect_only(self, intf, pkts, output, timeout=None):
        self.pg_send(intf, pkts)
        rx = output.get_capture(len(pkts))
        outputs = [output]
        if not timeout:
            timeout = 1
        for i in self.pg_interfaces:
            if i not in outputs:
                i.get_capture(0, timeout=timeout)
                i.assert_nothing_captured()
                timeout = 0.1

        return rx


def get_testcase_doc_name(test):
    return getdoc(test.__class__).splitlines()[0]


def get_test_description(descriptions, test):
    short_description = test.shortDescription()
    if descriptions and short_description:
        return short_description
    else:
        return str(test)


class TestCaseInfo(object):
    def __init__(self, logger, tempdir, vpp_pid, vpp_bin_path):
        self.logger = logger
        self.tempdir = tempdir
        self.vpp_pid = vpp_pid
        self.vpp_bin_path = vpp_bin_path
        self.core_crash_test = None


class VppTestResult(unittest.TestResult):
    """
    @property result_string
     String variable to store the test case result string.
    @property errors
     List variable containing 2-tuples of TestCase instances and strings
     holding formatted tracebacks. Each tuple represents a test which
     raised an unexpected exception.
    @property failures
     List variable containing 2-tuples of TestCase instances and strings
     holding formatted tracebacks. Each tuple represents a test where
     a failure was explicitly signalled using the TestCase.assert*()
     methods.
    """

    failed_test_cases_info = set()
    core_crash_test_cases_info = set()
    current_test_case_info = None

    def __init__(self, stream=None, descriptions=None, verbosity=None,
                 runner=None):
        """
        :param stream File descriptor to store where to report test results.
            Set to the standard error stream by default.
        :param descriptions Boolean variable to store information if to use
            test case descriptions.
        :param verbosity Integer variable to store required verbosity level.
        """
        super(VppTestResult, self).__init__(stream, descriptions, verbosity)
        self.stream = stream
        self.descriptions = descriptions
        self.verbosity = verbosity
        self.result_string = None
        self.runner = runner
        self.printed = []

    def addSuccess(self, test):
        """
        Record a test succeeded result

        :param test:

        """
        if self.current_test_case_info:
            self.current_test_case_info.logger.debug(
                "--- addSuccess() %s.%s(%s) called" % (test.__class__.__name__,
                                                       test._testMethodName,
                                                       test._testMethodDoc))
        unittest.TestResult.addSuccess(self, test)
        self.result_string = colorize("OK", GREEN)

        self.send_result_through_pipe(test, PASS)

    def addSkip(self, test, reason):
        """
        Record a test skipped.

        :param test:
        :param reason:

        """
        if self.current_test_case_info:
            self.current_test_case_info.logger.debug(
                "--- addSkip() %s.%s(%s) called, reason is %s" %
                (test.__class__.__name__, test._testMethodName,
                 test._testMethodDoc, reason))
        unittest.TestResult.addSkip(self, test, reason)
        self.result_string = colorize("SKIP", YELLOW)

        if reason == "not enough cpus":
            self.send_result_through_pipe(test, SKIP_CPU_SHORTAGE)
        else:
            self.send_result_through_pipe(test, SKIP)

    def symlink_failed(self):
        if self.current_test_case_info:
            try:
                failed_dir = config.failed_dir
                link_path = os.path.join(
                    failed_dir,
                    '%s-FAILED' %
                    os.path.basename(self.current_test_case_info.tempdir))

                self.current_test_case_info.logger.debug(
                    "creating a link to the failed test")
                self.current_test_case_info.logger.debug(
                    "os.symlink(%s, %s)" %
                    (self.current_test_case_info.tempdir, link_path))
                if os.path.exists(link_path):
                    self.current_test_case_info.logger.debug(
                        'symlink already exists')
                else:
                    os.symlink(self.current_test_case_info.tempdir, link_path)

            except Exception as e:
                self.current_test_case_info.logger.error(e)

    def send_result_through_pipe(self, test, result):
        if hasattr(self, 'test_framework_result_pipe'):
            pipe = self.test_framework_result_pipe
            if pipe:
                pipe.send((test.id(), result))

    def log_error(self, test, err, fn_name):
        if self.current_test_case_info:
            if isinstance(test, unittest.suite._ErrorHolder):
                test_name = test.description
            else:
                test_name = '%s.%s(%s)' % (test.__class__.__name__,
                                           test._testMethodName,
                                           test._testMethodDoc)
            self.current_test_case_info.logger.debug(
                "--- %s() %s called, err is %s" %
                (fn_name, test_name, err))
            self.current_test_case_info.logger.debug(
                "formatted exception is:\n%s" %
                "".join(format_exception(*err)))

    def add_error(self, test, err, unittest_fn, error_type):
        if error_type == FAIL:
            self.log_error(test, err, 'addFailure')
            error_type_str = colorize("FAIL", RED)
        elif error_type == ERROR:
            self.log_error(test, err, 'addError')
            error_type_str = colorize("ERROR", RED)
        else:
            raise Exception('Error type %s cannot be used to record an '
                            'error or a failure' % error_type)

        unittest_fn(self, test, err)
        if self.current_test_case_info:
            self.result_string = "%s [ temp dir used by test case: %s ]" % \
                                 (error_type_str,
                                  self.current_test_case_info.tempdir)
            self.symlink_failed()
            self.failed_test_cases_info.add(self.current_test_case_info)
            if is_core_present(self.current_test_case_info.tempdir):
                if not self.current_test_case_info.core_crash_test:
                    if isinstance(test, unittest.suite._ErrorHolder):
                        test_name = str(test)
                    else:
                        test_name = "'{!s}' ({!s})".format(
                            get_testcase_doc_name(test), test.id())
                    self.current_test_case_info.core_crash_test = test_name
                self.core_crash_test_cases_info.add(
                    self.current_test_case_info)
        else:
            self.result_string = '%s [no temp dir]' % error_type_str

        self.send_result_through_pipe(test, error_type)

    def addFailure(self, test, err):
        """
        Record a test failed result

        :param test:
        :param err: error message

        """
        self.add_error(test, err, unittest.TestResult.addFailure, FAIL)

    def addError(self, test, err):
        """
        Record a test error result

        :param test:
        :param err: error message

        """
        self.add_error(test, err, unittest.TestResult.addError, ERROR)

    def getDescription(self, test):
        """
        Get test description

        :param test:
        :returns: test description

        """
        return get_test_description(self.descriptions, test)

    def startTest(self, test):
        """
        Start a test

        :param test:

        """

        def print_header(test):
            if test.__class__ in self.printed:
                return

            test_doc = getdoc(test)
            if not test_doc:
                raise Exception("No doc string for test '%s'" % test.id())

            test_title = test_doc.splitlines()[0].rstrip()
            test_title = colorize(test_title, GREEN)
            if test.is_tagged_run_solo():
                test_title = colorize(f"SOLO RUN: {test_title}", YELLOW)

            # This block may overwrite the colorized title above,
            # but we want this to stand out and be fixed
            if test.has_tag(TestCaseTag.FIXME_VPP_WORKERS):
                test_title = colorize(
                    f"FIXME with VPP workers: {test_title}", RED)

            if test.has_tag(TestCaseTag.FIXME_ASAN):
                test_title = colorize(
                    f"FIXME with ASAN: {test_title}", RED)
                test.skip_fixme_asan()

            if hasattr(test, 'vpp_worker_count'):
                if test.vpp_worker_count == 0:
                    test_title += " [main thread only]"
                elif test.vpp_worker_count == 1:
                    test_title += " [1 worker thread]"
                else:
                    test_title += f" [{test.vpp_worker_count} worker threads]"

            if test.__class__.skipped_due_to_cpu_lack:
                test_title = colorize(
                    f"{test_title} [skipped - not enough cpus, "
                    f"required={test.__class__.get_cpus_required()}, "
                    f"available={max_vpp_cpus}]", YELLOW)

            print(double_line_delim)
            print(test_title)
            print(double_line_delim)
            self.printed.append(test.__class__)

        print_header(test)
        self.start_test = time.time()
        unittest.TestResult.startTest(self, test)
        if self.verbosity > 0:
            self.stream.writeln(
                "Starting " + self.getDescription(test) + " ...")
            self.stream.writeln(single_line_delim)

    def stopTest(self, test):
        """
        Called when the given test has been run

        :param test:

        """
        unittest.TestResult.stopTest(self, test)

        if self.verbosity > 0:
            self.stream.writeln(single_line_delim)
            self.stream.writeln("%-73s%s" % (self.getDescription(test),
                                             self.result_string))
            self.stream.writeln(single_line_delim)
        else:
            self.stream.writeln("%-68s %4.2f %s" %
                                (self.getDescription(test),
                                 time.time() - self.start_test,
                                 self.result_string))

        self.send_result_through_pipe(test, TEST_RUN)

    def printErrors(self):
        """
        Print errors from running the test case
        """
        if len(self.errors) > 0 or len(self.failures) > 0:
            self.stream.writeln()
            self.printErrorList('ERROR', self.errors)
            self.printErrorList('FAIL', self.failures)

        # ^^ that is the last output from unittest before summary
        if not self.runner.print_summary:
            devnull = unittest.runner._WritelnDecorator(open(os.devnull, 'w'))
            self.stream = devnull
            self.runner.stream = devnull

    def printErrorList(self, flavour, errors):
        """
        Print error list to the output stream together with error type
        and test case description.

        :param flavour: error type
        :param errors: iterable errors

        """
        for test, err in errors:
            self.stream.writeln(double_line_delim)
            self.stream.writeln("%s: %s" %
                                (flavour, self.getDescription(test)))
            self.stream.writeln(single_line_delim)
            self.stream.writeln("%s" % err)


class VppTestRunner(unittest.TextTestRunner):
    """
    A basic test runner implementation which prints results to standard error.
    """

    @property
    def resultclass(self):
        """Class maintaining the results of the tests"""
        return VppTestResult

    def __init__(self, keep_alive_pipe=None, descriptions=True, verbosity=1,
                 result_pipe=None, failfast=False, buffer=False,
                 resultclass=None, print_summary=True, **kwargs):
        # ignore stream setting here, use hard-coded stdout to be in sync
        # with prints from VppTestCase methods ...
        super(VppTestRunner, self).__init__(sys.stdout, descriptions,
                                            verbosity, failfast, buffer,
                                            resultclass, **kwargs)
        KeepAliveReporter.pipe = keep_alive_pipe

        self.orig_stream = self.stream
        self.resultclass.test_framework_result_pipe = result_pipe

        self.print_summary = print_summary

    def _makeResult(self):
        return self.resultclass(self.stream,
                                self.descriptions,
                                self.verbosity,
                                self)

    def run(self, test):
        """
        Run the tests

        :param test:

        """
        faulthandler.enable()  # emit stack trace to stderr if killed by signal

        result = super(VppTestRunner, self).run(test)
        if not self.print_summary:
            self.stream = self.orig_stream
            result.stream = self.orig_stream
        return result


class Worker(Thread):
    def __init__(self, executable_args, logger, env=None, *args, **kwargs):
        super(Worker, self).__init__(*args, **kwargs)
        self.logger = logger
        self.args = executable_args
        if hasattr(self, 'testcase') and self.testcase.debug_all:
            if self.testcase.debug_gdbserver:
                self.args = ['/usr/bin/gdbserver', 'localhost:{port}'
                             .format(port=self.testcase.gdbserver_port)] + args
            elif self.testcase.debug_gdb and hasattr(self, 'wait_for_gdb'):
                self.args.append(self.wait_for_gdb)
        self.app_bin = executable_args[0]
        self.app_name = os.path.basename(self.app_bin)
        if hasattr(self, 'role'):
            self.app_name += ' {role}'.format(role=self.role)
        self.process = None
        self.result = None
        env = {} if env is None else env
        self.env = copy.deepcopy(env)

    def wait_for_enter(self):
        if not hasattr(self, 'testcase'):
            return
        if self.testcase.debug_all and self.testcase.debug_gdbserver:
            print()
            print(double_line_delim)
            print("Spawned GDB Server for '{app}' with PID: {pid}"
                  .format(app=self.app_name, pid=self.process.pid))
        elif self.testcase.debug_all and self.testcase.debug_gdb:
            print()
            print(double_line_delim)
            print("Spawned '{app}' with PID: {pid}"
                  .format(app=self.app_name, pid=self.process.pid))
        else:
            return
        print(single_line_delim)
        print("You can debug '{app}' using:".format(app=self.app_name))
        if self.testcase.debug_gdbserver:
            print("sudo gdb " + self.app_bin +
                  " -ex 'target remote localhost:{port}'"
                  .format(port=self.testcase.gdbserver_port))
            print("Now is the time to attach gdb by running the above "
                  "command, set up breakpoints etc., then resume from "
                  "within gdb by issuing the 'continue' command")
            self.testcase.gdbserver_port += 1
        elif self.testcase.debug_gdb:
            print("sudo gdb " + self.app_bin +
                  " -ex 'attach {pid}'".format(pid=self.process.pid))
            print("Now is the time to attach gdb by running the above "
                  "command and set up breakpoints etc., then resume from"
                  " within gdb by issuing the 'continue' command")
        print(single_line_delim)
        input("Press ENTER to continue running the testcase...")

    def run(self):
        executable = self.args[0]
        if not os.path.exists(executable) or not os.access(
                executable, os.F_OK | os.X_OK):
            # Exit code that means some system file did not exist,
            # could not be opened, or had some other kind of error.
            self.result = os.EX_OSFILE
            raise EnvironmentError(
                "executable '%s' is not found or executable." % executable)
        self.logger.debug("Running executable '{app}': '{cmd}'"
                          .format(app=self.app_name,
                                  cmd=' '.join(self.args)))
        env = os.environ.copy()
        env.update(self.env)
        env["CK_LOG_FILE_NAME"] = "-"
        self.process = subprocess.Popen(
            ['stdbuf', '-o0', '-e0'] + self.args, shell=False, env=env,
            preexec_fn=os.setpgrp, stdout=subprocess.PIPE,
            stderr=subprocess.PIPE)
        self.wait_for_enter()
        out, err = self.process.communicate()
        self.logger.debug("Finished running `{app}'".format(app=self.app_name))
        self.logger.info("Return code is `%s'" % self.process.returncode)
        self.logger.info(single_line_delim)
        self.logger.info("Executable `{app}' wrote to stdout:"
                         .format(app=self.app_name))
        self.logger.info(single_line_delim)
        self.logger.info(out.decode('utf-8'))
        self.logger.info(single_line_delim)
        self.logger.info("Executable `{app}' wrote to stderr:"
                         .format(app=self.app_name))
        self.logger.info(single_line_delim)
        self.logger.info(err.decode('utf-8'))
        self.logger.info(single_line_delim)
        self.result = self.process.returncode


if __name__ == '__main__':
    pass