pg: A Tunnel mode variant of a pg interface
[vpp.git] / test / framework.py
old mode 100644 (file)
new mode 100755 (executable)
index 47de2c4..2afec7a
@@ -1,10 +1,13 @@
-#!/usr/bin/env python
+#!/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 tempfile
 import time
@@ -18,16 +21,21 @@ 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
 
 import scapy.compat
 from scapy.packet import Raw
-from hook import StepHook, PollHook, VppDiedError
+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
@@ -36,28 +44,43 @@ from scapy.layers.inet import IPerror, TCPerror, UDPerror, ICMPerror
 from scapy.layers.inet6 import ICMPv6DestUnreach, ICMPv6EchoRequest
 from scapy.layers.inet6 import ICMPv6EchoReply
 
-if os.name == 'posix' and sys.version_info[0] < 3:
-    # using subprocess32 is recommended by python official documentation
-    # @ https://docs.python.org/2/library/subprocess.html
-    import subprocess32 as subprocess
-else:
-    import subprocess
-
-#  Python2/3 compatible
-try:
-    input = raw_input
-except NameError:
-    pass
+from cpu_config import available_cpus, num_cpus, max_vpp_cpus
+
+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
+
+
+class BoolEnvironmentVariable(object):
+
+    def __init__(self, env_var_name, default='n', true_values=None):
+        self.name = env_var_name
+        self.default = default
+        self.true_values = true_values if true_values is not None else \
+            ("y", "yes", "1")
+
+    def __bool__(self):
+        return os.getenv(self.name, self.default).lower() in self.true_values
+
+    if sys.version_info[0] == 2:
+        __nonzero__ = __bool__
+
+    def __repr__(self):
+        return 'BoolEnvironmentVariable(%r, default=%r, true_values=%r)' % \
+               (self.name, self.default, self.true_values)
+
 
-debug_framework = False
-if os.getenv('TEST_DEBUG', "0") == "1":
-    debug_framework = True
+debug_framework = BoolEnvironmentVariable('TEST_DEBUG')
+if debug_framework:
     import debug_internal
 
 """
@@ -68,6 +91,39 @@ if os.getenv('TEST_DEBUG', "0") == "1":
 """
 
 
+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.
 
@@ -108,7 +164,8 @@ def pump_output(testclass):
         if testclass.vpp.stdout.fileno() in readable:
             read = os.read(testclass.vpp.stdout.fileno(), 102400)
             if len(read) > 0:
-                split = read.splitlines(True)
+                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"):
@@ -119,30 +176,33 @@ def pump_output(testclass):
                 testclass.vpp_stdout_deque.extend(split[:limit])
                 if not testclass.cache_vpp_output:
                     for line in split[:limit]:
-                        testclass.logger.debug(
+                        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.splitlines(True)
+                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(b"\n"):
+                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 testclass.cache_vpp_output:
                     for line in split[:limit]:
-                        testclass.logger.debug(
+                        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_skip_aarch64_set():
-    return os.getenv('SKIP_AARCH64', 'n').lower() in ('yes', 'y', '1')
+    return BoolEnvironmentVariable('SKIP_AARCH64')
+
 
 is_skip_aarch64_set = _is_skip_aarch64_set()
 
@@ -150,21 +210,37 @@ is_skip_aarch64_set = _is_skip_aarch64_set()
 def _is_platform_aarch64():
     return platform.machine() == 'aarch64'
 
+
 is_platform_aarch64 = _is_platform_aarch64()
 
 
 def _running_extended_tests():
-    s = os.getenv("EXTENDED_TESTS", "n")
-    return True if s.lower() in ("y", "yes", "1") else False
+    return BoolEnvironmentVariable("EXTENDED_TESTS")
+
 
 running_extended_tests = _running_extended_tests()
 
 
-def _running_on_centos():
-    os_id = os.getenv("OS_ID", "")
-    return True if "centos" in os_id.lower() else False
+def _running_gcov_tests():
+    return BoolEnvironmentVariable("GCOV_TESTS")
+
+
+running_gcov_tests = _running_gcov_tests()
 
-running_on_centos = _running_on_centos
+
+def get_environ_vpp_worker_count():
+    worker_config = os.getenv("VPP_WORKER_CONFIG", None)
+    if worker_config:
+        elems = worker_config.split(" ")
+        if elems[0] != "workers" or len(elems) != 2:
+            raise ValueError("Wrong VPP_WORKER_CONFIG == '%s' value." %
+                             worker_config)
+        return int(elems[1])
+    else:
+        return 0
+
+
+environ_vpp_worker_count = get_environ_vpp_worker_count()
 
 
 class KeepAliveReporter(object):
@@ -203,13 +279,63 @@ class KeepAliveReporter(object):
         self.pipe.send((desc, test.vpp_bin, test.tempdir, test.vpp.pid))
 
 
-class VppTestCase(unittest.TestCase):
+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
+
+
+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)
+
+
+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):
@@ -224,6 +350,20 @@ class VppTestCase(unittest.TestCase):
         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 instance(cls):
         """Return the instance of this testcase"""
@@ -231,59 +371,48 @@ class VppTestCase(unittest.TestCase):
 
     @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":
+        elif dl == "gdb" or dl == "gdb-all":
             cls.debug_gdb = True
-        elif dl == "gdbserver":
+        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
 
-    @staticmethod
-    def get_least_used_cpu():
-        cpu_usage_list = [set(range(psutil.cpu_count()))]
-        vpp_processes = [p for p in psutil.process_iter(attrs=['pid', 'name'])
-                         if 'vpp_main' == p.info['name']]
-        for vpp_process in vpp_processes:
-            for cpu_usage_set in cpu_usage_list:
-                try:
-                    cpu_num = vpp_process.cpu_num()
-                    if cpu_num in cpu_usage_set:
-                        cpu_usage_set_index = cpu_usage_list.index(
-                            cpu_usage_set)
-                        if cpu_usage_set_index == len(cpu_usage_list) - 1:
-                            cpu_usage_list.append({cpu_num})
-                        else:
-                            cpu_usage_list[cpu_usage_set_index + 1].add(
-                                cpu_num)
-                        cpu_usage_set.remove(cpu_num)
-                        break
-                except psutil.NoSuchProcess:
-                    pass
-
-        for cpu_usage_set in cpu_usage_list:
-            if len(cpu_usage_set) > 0:
-                min_usage_set = cpu_usage_set
-                break
+    @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 = environ_vpp_worker_count
+        return cls.vpp_worker_count
 
-        return random.choice(tuple(min_usage_set))
+    @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 """
-        s = os.getenv("STEP", "n")
-        cls.step = True if s.lower() in ("y", "yes", "1") else False
-        d = os.getenv("DEBUG", None)
+        cls.step = BoolEnvironmentVariable('STEP')
+        # inverted case to handle '' == True
         c = os.getenv("CACHE_OUTPUT", "1")
         cls.cache_vpp_output = False if c.lower() in ("n", "no", "0") else True
-        cls.set_debug_flags(d)
         cls.vpp_bin = os.getenv('VPP_BIN', "vpp")
         cls.plugin_path = os.getenv('VPP_PLUGIN_PATH')
         cls.test_plugin_path = os.getenv('VPP_TEST_PLUGIN_PATH')
@@ -307,21 +436,40 @@ class VppTestCase(unittest.TestCase):
         if coredump_size is None:
             coredump_size = "coredump-size unlimited"
 
-        cpu_core_number = cls.get_least_used_cpu()
-
-        cls.vpp_cmdline = [cls.vpp_bin, "unix",
-                           "{", "nodaemon", debug_cli, "full-coredump",
-                           coredump_size, "runtime-dir", cls.tempdir, "}",
-                           "api-trace", "{", "on", "}", "api-segment", "{",
-                           "prefix", cls.shm_prefix, "}", "cpu", "{",
-                           "main-core", str(cpu_core_number), "}",
-                           "statseg", "{", "socket-name", cls.stats_sock, "}",
-                           "socksvr", "{", "socket-name", cls.api_sock, "}",
-                           "plugins",
-                           "{", "plugin", "dpdk_plugin.so", "{", "disable",
-                           "}", "plugin", "rdma_plugin.so", "{", "disable",
-                           "}", "plugin", "unittest_plugin.so", "{", "enable",
-                           "}"] + cls.extra_vpp_plugin_config + ["}", ]
+        default_variant = os.getenv("VARIANT")
+        if default_variant is not None:
+            default_variant = "defaults { %s 100 }" % default_variant
+        else:
+            default_variant = ""
+
+        api_fuzzing = os.getenv("API_FUZZ")
+        if api_fuzzing is None:
+            api_fuzzing = 'off'
+
+        cls.vpp_cmdline = [
+            cls.vpp_bin,
+            "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.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 plugin_path is not None:
@@ -329,8 +477,9 @@ class VppTestCase(unittest.TestCase):
         if cls.test_plugin_path is not None:
             cls.vpp_cmdline.extend(["test_plugin_path", cls.test_plugin_path])
 
-        cls.logger.info("vpp_cmdline args: %s" % cls.vpp_cmdline)
-        cls.logger.info("vpp_cmdline: %s" % " ".join(cls.vpp_cmdline))
+        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):
@@ -344,38 +493,47 @@ class VppTestCase(unittest.TestCase):
             cls.logger.debug("Spawned VPP with PID: %d" % cls.vpp.pid)
             return
         print(single_line_delim)
-        print("You can debug the VPP using e.g.:")
+        print("You can debug VPP using:")
         if cls.debug_gdbserver:
-            print("gdb " + cls.vpp_bin + " -ex 'target remote localhost:7777'")
-            print("Now is the time to attach a gdb by running the above "
-                  "command, set up breakpoints etc. and then resume VPP from "
+            print("sudo gdb " + cls.vpp_bin +
+                  " -ex 'target remote localhost:{port}'"
+                  .format(port=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("gdb " + cls.vpp_bin + " -ex 'attach %s'" % cls.vpp.pid)
-            print("Now is the time to attach a gdb by running the above "
-                  "command and set up breakpoints etc.")
+            print("sudo gdb " + cls.vpp_bin + " -ex 'attach %s'" % 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 \
+            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:7777'] + cls.vpp_cmdline
+            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,
-                                       bufsize=1)
+                                       stderr=subprocess.PIPE)
         except subprocess.CalledProcessError as e:
             cls.logger.critical("Subprocess returned with non-0 return code: ("
                                 "%s)", e.returncode)
@@ -391,19 +549,6 @@ class VppTestCase(unittest.TestCase):
 
         cls.wait_for_enter()
 
-    @classmethod
-    def wait_for_stats_socket(cls):
-        deadline = time.time() + 3
-        ok = False
-        while time.time() < deadline or \
-                cls.debug_gdb or cls.debug_gdbserver:
-            if os.path.exists(cls.stats_sock):
-                ok = True
-                break
-            cls.sleep(0.8)
-        if not ok:
-            cls.logger.critical("Couldn't stat : {}".format(cls.stats_sock))
-
     @classmethod
     def wait_for_coredump(cls):
         corefile = cls.tempdir + "/core"
@@ -426,6 +571,26 @@ class VppTestCase(unittest.TestCase):
                 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):
+        if cls.debug_attach:
+            return os.getenv("VPP_IN_GDB_TMP_DIR",
+                             "/tmp/unittest-attach-gdb")
+        else:
+            return tempfile.mkdtemp(prefix='vpp-unittest-%s-' % cls.__name__)
+
     @classmethod
     def setUpClass(cls):
         """
@@ -433,33 +598,30 @@ class VppTestCase(unittest.TestCase):
         Remove shared memory files, start vpp and connect the vpp-api
         """
         super(VppTestCase, cls).setUpClass()
-        gc.collect()  # run garbage collection first
-        random.seed()
         cls.logger = get_logger(cls.__name__)
+        seed = os.environ["RND_SEED"]
+        random.seed(seed)
         if hasattr(cls, 'parallel_handler'):
             cls.logger.addHandler(cls.parallel_handler)
             cls.logger.propagate = False
-
-        cls.tempdir = tempfile.mkdtemp(
-            prefix='vpp-unittest-%s-' % cls.__name__)
-        cls.stats_sock = "%s/stats.sock" % cls.tempdir
-        cls.api_sock = "%s/api.sock" % cls.tempdir
+        d = os.getenv("DEBUG", None)
+        cls.set_debug_flags(d)
+        cls.tempdir = cls.get_tempdir()
         cls.file_handler = FileHandler("%s/log.txt" % cls.tempdir)
         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__)
-        cls.shm_prefix = os.path.basename(cls.tempdir)
+        cls.logger.debug("--- setUpClass() for %s called ---" % cls.__name__)
         os.chdir(cls.tempdir)
-        cls.logger.info("Temporary dir is %s, shm prefix is %s",
-                        cls.tempdir, cls.shm_prefix)
+        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", seed)
         cls.setUpConstants()
         cls.reset_packet_infos()
-        cls._captures = []
-        cls._zombie_captures = []
+        cls._pcaps = []
+        cls._old_pcaps = []
         cls.verbose = 0
         cls.vpp_dead = False
         cls.registry = VppObjectRegistry()
@@ -468,30 +630,31 @@ class VppTestCase(unittest.TestCase):
         # 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:
-            cls.run_vpp()
+            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, cls.vpp_bin)
             cls.vpp_stdout_deque = deque()
             cls.vpp_stderr_deque = deque()
-            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:
-                read_timeout = 0
-            else:
-                read_timeout = 5
-            cls.vapi = VppPapiProvider(cls.shm_prefix, cls.shm_prefix, cls,
-                                       read_timeout)
+            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 = StepHook(cls)
+                hook = hookmodule.StepHook(cls)
             else:
-                hook = PollHook(cls)
+                hook = hookmodule.PollHook(cls)
             cls.vapi.register_hook(hook)
-            cls.wait_for_stats_socket()
-            cls.statistics = VPPStats(socketname=cls.stats_sock)
+            cls.statistics = VPPStats(socketname=cls.get_stats_sock_path())
             try:
                 hook.poll_vpp()
             except VppDiedError:
@@ -502,36 +665,50 @@ class VppTestCase(unittest.TestCase):
                 raise
             try:
                 cls.vapi.connect()
-            except Exception:
-                try:
-                    cls.vapi.disconnect()
-                except Exception:
-                    pass
+            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
-        except Exception:
+                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.quit()
-            except Exception:
+                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
-            raise
 
     @classmethod
     def quit(cls):
         """
         Disconnect vpp-api, kill vpp and cleanup shared memory files
         """
-        if (cls.debug_gdbserver or cls.debug_gdb) and hasattr(cls, 'vpp'):
-            cls.vpp.poll()
-            if cls.vpp.returncode is None:
-                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...")
+        cls._debug_quit()
 
         # first signal that we want to stop the pump thread, then wake it up
         if hasattr(cls, 'pump_thread_stop_flag'):
@@ -542,11 +719,12 @@ class VppTestCase(unittest.TestCase):
             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 stdderr pump to stop")
+            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()
@@ -554,14 +732,21 @@ class VppTestCase(unittest.TestCase):
                                  cls.__name__)
                 del cls.vapi
             cls.vpp.poll()
-            if cls.vpp.returncode is None:
+            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")
-                cls.vpp.communicate()
+                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:
@@ -612,20 +797,22 @@ class VppTestCase(unittest.TestCase):
         self.logger.debug("--- tearDown() for %s.%s(%s) called ---" %
                           (self.__class__.__name__, self._testMethodName,
                            self._testMethodDoc))
-        if not self.vpp_dead:
-            self.logger.info(
-                "--- Logging show commands common to all testcases. ---")
-            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("Logging testcase specific show commands.")
-            self.show_commands_at_teardown()
-            self.registry.remove_vpp_config(self.logger)
+
+        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
-            api_trace = "vpp_api_trace.%s.log" % self._testMethodName
+            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))
@@ -634,6 +821,10 @@ class VppTestCase(unittest.TestCase):
             os.rename(tmp_api_trace, vpp_api_trace_log)
             self.logger.info(self.vapi.ppcli("api trace custom-dump %s" %
                                              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)
 
@@ -642,7 +833,8 @@ class VppTestCase(unittest.TestCase):
         super(VppTestCase, self).setUp()
         self.reporter.send_keep_alive(self)
         if self.vpp_dead:
-            raise Exception("VPP is dead when setting up the test")
+            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" %
@@ -672,37 +864,60 @@ class VppTestCase(unittest.TestCase):
             i.enable_capture()
 
     @classmethod
-    def register_capture(cls, cap_name):
-        """ Register a capture in the testclass """
+    def register_pcap(cls, intf, worker):
+        """ Register a pcap in the testclass """
         # add to the list of captures with current timestamp
-        cls._captures.append((time.time(), cap_name))
-        # filter out from zombies
-        cls._zombie_captures = [(stamp, name)
-                                for (stamp, name) in cls._zombie_captures
-                                if name != cap_name]
+        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 pg_start(cls):
-        """ Remove any zombie captures and enable the packet generator """
-        # how long before capture is allowed to be deleted - otherwise vpp
-        # crashes - 100ms seems enough (this shouldn't be needed at all)
-        capture_ttl = 0.1
-        now = time.time()
-        for stamp, cap_name in cls._zombie_captures:
-            wait = stamp + capture_ttl - now
-            if wait > 0:
-                cls.sleep(wait, "before deleting capture %s" % cap_name)
-                now = time.time()
-            cls.logger.debug("Removing zombie capture %s" % cap_name)
-            cls.vapi.cli('packet-generator delete %s' % cap_name)
-
-        cls.vapi.cli("trace add pg-input 1000")
+    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.rename_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')
-        cls._zombie_captures = cls._captures
-        cls._captures = []
+        # 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(cls, interfaces):
+    def create_pg_interfaces_internal(cls, interfaces, gso=0, gso_size=0,
+                                      mode=None):
         """
         Create packet-generator interfaces.
 
@@ -712,12 +927,36 @@ class VppTestCase(unittest.TestCase):
         """
         result = []
         for i in interfaces:
-            intf = VppPGInterface(cls, i)
+            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):
         """
@@ -913,8 +1152,6 @@ class VppTestCase(unittest.TestCase):
     def assert_packet_checksums_valid(self, packet,
                                       ignore_zero_udp_checksums=True):
         received = packet.__class__(scapy.compat.raw(packet))
-        self.logger.debug(
-            ppp("Verifying packet checksums for packet:", received))
         udp_layers = ['UDP', 'UDPerror']
         checksum_fields = ['cksum', 'chksum']
         checksums = []
@@ -923,13 +1160,15 @@ class VppTestCase(unittest.TestCase):
         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:
+                                0 == getattr(layer, cf) and \
+                                layer.name in udp_layers:
                             continue
-                        delattr(layer, cf)
+                        delattr(temp.getlayer(counter), cf)
                         checksums.append((counter, cf))
             else:
                 break
@@ -1000,19 +1239,28 @@ class VppTestCase(unittest.TestCase):
         if pkt.haslayer(ICMPv6EchoReply):
             self.assert_checksum_valid(pkt, 'ICMPv6EchoReply', 'cksum')
 
-    def assert_packet_counter_equal(self, counter, expected_value):
+    def get_packet_counter(self, counter):
         if counter.startswith("/"):
             counter_value = self.statistics.get_counter(counter)
-            self.assert_equal(counter_value, expected_value,
-                              "packet counter `%s'" % counter)
         else:
             counters = self.vapi.cli("sh errors").split('\n')
-            counter_value = -1
+            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):
@@ -1029,25 +1277,23 @@ class VppTestCase(unittest.TestCase):
                 time.sleep(0)
             return
 
-        if hasattr(cls, 'logger'):
-            cls.logger.debug("Starting sleep for %es (%s)", timeout, remark)
+        cls.logger.debug("Starting sleep for %es (%s)", timeout, remark)
         before = time.time()
         time.sleep(timeout)
         after = time.time()
-        if hasattr(cls, 'logger') and after - before > 2 * timeout:
+        if after - before > 2 * timeout:
             cls.logger.error("unexpected self.sleep() result - "
                              "slept for %es instead of ~%es!",
                              after - before, timeout)
-        if hasattr(cls, 'logger'):
-            cls.logger.debug(
-                "Finished sleep (%s) - slept %es (wanted %es)",
-                remark, after - before, timeout)
 
-    def pg_send(self, intf, pkts):
-        self.vapi.cli("clear trace")
-        intf.add_stream(pkts)
+        cls.logger.debug(
+            "Finished sleep (%s) - slept %es (wanted %es)",
+            remark, after - before, 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()
+        self.pg_start(trace=trace)
 
     def send_and_assert_no_replies(self, intf, pkts, remark="", timeout=None):
         self.pg_send(intf, pkts)
@@ -1058,10 +1304,11 @@ class VppTestCase(unittest.TestCase):
             i.assert_nothing_captured(remark=remark)
             timeout = 0.1
 
-    def send_and_expect(self, intf, pkts, output, n_rx=None):
+    def send_and_expect(self, intf, pkts, output, n_rx=None, worker=None,
+                        trace=True):
         if not n_rx:
             n_rx = len(pkts)
-        self.pg_send(intf, pkts)
+        self.pg_send(intf, pkts, worker=worker, trace=trace)
         rx = output.get_capture(n_rx)
         return rx
 
@@ -1079,11 +1326,6 @@ class VppTestCase(unittest.TestCase):
 
         return rx
 
-    def runTest(self):
-        """ unittest calls runTest when TestCase is instantiated without a
-        test case.  Use case: Writing unittests against VppTestCase"""
-        pass
-
 
 def get_testcase_doc_name(test):
     return getdoc(test.__class__).splitlines()[0]
@@ -1140,6 +1382,7 @@ class VppTestResult(unittest.TestResult):
         self.verbosity = verbosity
         self.result_string = None
         self.runner = runner
+        self.printed = []
 
     def addSuccess(self, test):
         """
@@ -1174,7 +1417,10 @@ class VppTestResult(unittest.TestResult):
         unittest.TestResult.addSkip(self, test, reason)
         self.result_string = colorize("SKIP", YELLOW)
 
-        self.send_result_through_pipe(test, SKIP)
+        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:
@@ -1184,22 +1430,20 @@ class VppTestResult(unittest.TestResult):
                     failed_dir,
                     '%s-FAILED' %
                     os.path.basename(self.current_test_case_info.tempdir))
-                if self.current_test_case_info.logger:
-                    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))
+
+                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):
-                    if self.current_test_case_info.logger:
-                        self.current_test_case_info.logger.debug(
-                            'symlink already exists')
+                    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:
-                if self.current_test_case_info.logger:
-                    self.current_test_case_info.logger.error(e)
+                self.current_test_case_info.logger.error(e)
 
     def send_result_through_pipe(self, test, result):
         if hasattr(self, 'test_framework_result_pipe'):
@@ -1294,14 +1538,45 @@ class VppTestResult(unittest.TestResult):
         """
 
         def print_header(test):
-            if not hasattr(test.__class__, '_header_printed'):
-                print(double_line_delim)
-                print(colorize(getdoc(test).splitlines()[0], GREEN))
-                print(double_line_delim)
-            test.__class__._header_printed = True
+            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 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]"
 
-        print_header(test)
+            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(
@@ -1316,14 +1591,17 @@ class VppTestResult(unittest.TestResult):
 
         """
         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("%-73s%s" % (self.getDescription(test),
-                                             self.result_string))
+            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)
 
@@ -1407,35 +1685,95 @@ class VppTestRunner(unittest.TextTestRunner):
 
 
 class Worker(Thread):
-    def __init__(self, args, logger, env={}):
+    def __init__(self, executable_args, logger, env=None, *args, **kwargs):
+        super(Worker, self).__init__(*args, **kwargs)
         self.logger = logger
-        self.args = args
+        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)
-        super(Worker, self).__init__()
+
+    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]
-        self.logger.debug("Running executable w/args `%s'" % self.args)
+        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(
-            self.args, shell=False, env=env, preexec_fn=os.setpgrp,
-            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+            ['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 `%s'" % executable)
+        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 `%s' wrote to stdout:" % executable)
+        self.logger.info("Executable `{app}' wrote to stdout:"
+                         .format(app=self.app_name))
         self.logger.info(single_line_delim)
-        self.logger.info(out)
+        self.logger.info(out.decode('utf-8'))
         self.logger.info(single_line_delim)
-        self.logger.info("Executable `%s' wrote to stderr:" % executable)
+        self.logger.info("Executable `{app}' wrote to stderr:"
+                         .format(app=self.app_name))
         self.logger.info(single_line_delim)
-        self.logger.info(err)
+        self.logger.info(err.decode('utf-8'))
         self.logger.info(single_line_delim)
         self.result = self.process.returncode
 
+
 if __name__ == '__main__':
     pass