test/run_tests.py

#!/usr/bin/env python

import sys
import shutil
import os
import fnmatch
import unittest
import argparse
import time
import threading
import signal
import psutil
import re
from multiprocessing import Process, Pipe, cpu_count
from multiprocessing.queues import Queue
from multiprocessing.managers import BaseManager
from framework import VppTestRunner, running_extended_tests, VppTestCase, \
    get_testcase_doc_name, get_test_description, PASS, FAIL, ERROR, SKIP, \
    TEST_RUN
from debug import spawn_gdb
from log import get_parallel_logger, double_line_delim, RED, YELLOW, GREEN, \
    colorize, single_line_delim
from discover_tests import discover_tests
from subprocess import check_output, CalledProcessError
from util import check_core_path, get_core_path, is_core_present

# timeout which controls how long the child has to finish after seeing
# a core dump in test temporary directory. If this is exceeded, parent assumes
# that child process is stuck (e.g. waiting for shm mutex, which will never
# get unlocked) and kill the child
core_timeout = 3
min_req_shm = 536870912  # min 512MB shm required
# 128MB per extra process
shm_per_process = 134217728


class StreamQueue(Queue):
    def write(self, msg):
        self.put(msg)

    def flush(self):
        sys.__stdout__.flush()
        sys.__stderr__.flush()

    def fileno(self):
        return self._writer.fileno()


class StreamQueueManager(BaseManager):
    pass


StreamQueueManager.register('StreamQueue', StreamQueue)


class TestResult(dict):
    def __init__(self, testcase_suite, testcases_by_id=None):
        super(TestResult, self).__init__()
        self[PASS] = []
        self[FAIL] = []
        self[ERROR] = []
        self[SKIP] = []
        self[TEST_RUN] = []
        self.crashed = False
        self.testcase_suite = testcase_suite
        self.testcases = [testcase for testcase in testcase_suite]
        self.testcases_by_id = testcases_by_id

    def was_successful(self):
        return 0 == len(self[FAIL]) == len(self[ERROR]) \
            and len(self[PASS] + self[SKIP]) \
            == self.testcase_suite.countTestCases() == len(self[TEST_RUN])

    def no_tests_run(self):
        return 0 == len(self[TEST_RUN])

    def process_result(self, test_id, result):
        self[result].append(test_id)

    def suite_from_failed(self):
        rerun_ids = set([])
        for testcase in self.testcase_suite:
            tc_id = testcase.id()
            if tc_id not in self[PASS] and tc_id not in self[SKIP]:
                rerun_ids.add(tc_id)
        if rerun_ids:
            return suite_from_failed(self.testcase_suite, rerun_ids)

    def get_testcase_names(self, test_id):
        # could be tearDownClass (test_ipsec_esp.TestIpsecEsp1)
        setup_teardown_match = re.match(
            r'((tearDownClass)|(setUpClass)) \((.+\..+)\)', test_id)
        if setup_teardown_match:
            test_name, _, _, testcase_name = setup_teardown_match.groups()
            if len(testcase_name.split('.')) == 2:
                for key in self.testcases_by_id.keys():
                    if key.startswith(testcase_name):
                        testcase_name = key
                        break
            testcase_name = self._get_testcase_doc_name(testcase_name)
        else:
            test_name = self._get_test_description(test_id)
            testcase_name = self._get_testcase_doc_name(test_id)

        return testcase_name, test_name

    def _get_test_description(self, test_id):
        if test_id in self.testcases_by_id:
            desc = get_test_description(descriptions,
                                        self.testcases_by_id[test_id])
        else:
            desc = test_id
        return desc

    def _get_testcase_doc_name(self, test_id):
        if test_id in self.testcases_by_id:
            doc_name = get_testcase_doc_name(self.testcases_by_id[test_id])
        else:
            doc_name = test_id
        return doc_name


def test_runner_wrapper(suite, keep_alive_pipe, stdouterr_queue,
                        finished_pipe, result_pipe, logger):
    sys.stdout = stdouterr_queue
    sys.stderr = stdouterr_queue
    VppTestCase.parallel_handler = logger.handlers[0]
    result = VppTestRunner(keep_alive_pipe=keep_alive_pipe,
                           descriptions=descriptions,
                           verbosity=verbose,
                           result_pipe=result_pipe,
                           failfast=failfast,
                           print_summary=False).run(suite)
    finished_pipe.send(result.wasSuccessful())
    finished_pipe.close()
    keep_alive_pipe.close()


class TestCaseWrapper(object):
    def __init__(self, testcase_suite, manager):
        self.keep_alive_parent_end, self.keep_alive_child_end = Pipe(
            duplex=False)
        self.finished_parent_end, self.finished_child_end = Pipe(duplex=False)
        self.result_parent_end, self.result_child_end = Pipe(duplex=False)
        self.testcase_suite = testcase_suite
        if sys.version[0] == '2':
            self.stdouterr_queue = manager.StreamQueue()
        else:
            from multiprocessing import get_context
            self.stdouterr_queue = manager.StreamQueue(ctx=get_context())
        self.logger = get_parallel_logger(self.stdouterr_queue)
        self.child = Process(target=test_runner_wrapper,
                             args=(testcase_suite,
                                   self.keep_alive_child_end,
                                   self.stdouterr_queue,
                                   self.finished_child_end,
                                   self.result_child_end,
                                   self.logger)
                             )
        self.child.start()
        self.last_test_temp_dir = None
        self.last_test_vpp_binary = None
        self._last_test = None
        self.last_test_id = None
        self.vpp_pid = None
        self.last_heard = time.time()
        self.core_detected_at = None
        self.testcases_by_id = {}
        self.testclasess_with_core = {}
        for testcase in self.testcase_suite:
            self.testcases_by_id[testcase.id()] = testcase
        self.result = TestResult(testcase_suite, self.testcases_by_id)

    @property
    def last_test(self):
        return self._last_test

    @last_test.setter
    def last_test(self, test_id):
        self.last_test_id = test_id
        if test_id in self.testcases_by_id:
            testcase = self.testcases_by_id[test_id]
            self._last_test = testcase.shortDescription()
            if not self._last_test:
                self._last_test = str(testcase)
        else:
            self._last_test = test_id

    def add_testclass_with_core(self):
        if self.last_test_id in self.testcases_by_id:
            test = self.testcases_by_id[self.last_test_id]
            class_name = unittest.util.strclass(test.__class__)
            test_name = "'{}' ({})".format(get_test_description(descriptions,
                                                                test),
                                           self.last_test_id)
        else:
            test_name = self.last_test_id
            class_name = re.match(r'((tearDownClass)|(setUpClass)) '
                                  r'\((.+\..+)\)', test_name).groups()[3]
        if class_name not in self.testclasess_with_core:
            self.testclasess_with_core[class_name] = (
                test_name,
                self.last_test_vpp_binary,
                self.last_test_temp_dir)

    def close_pipes(self):
        self.keep_alive_child_end.close()
        self.finished_child_end.close()
        self.result_child_end.close()
        self.keep_alive_parent_end.close()
        self.finished_parent_end.close()
        self.result_parent_end.close()

    def was_successful(self):
        return self.result.was_successful()


def stdouterr_reader_wrapper(unread_testcases, finished_unread_testcases,
                             read_testcases):
    read_testcase = None
    while read_testcases.is_set() or unread_testcases:
        if finished_unread_testcases:
            read_testcase = finished_unread_testcases.pop()
            unread_testcases.remove(read_testcase)
        elif unread_testcases:
            read_testcase = unread_testcases.pop()
        if read_testcase:
            data = ''
            while data is not None:
                sys.stdout.write(data)
                data = read_testcase.stdouterr_queue.get()

            read_testcase.stdouterr_queue.close()
            finished_unread_testcases.discard(read_testcase)
            read_testcase = None


def handle_failed_suite(logger, last_test_temp_dir, vpp_pid):
    if last_test_temp_dir:
        # Need to create link in case of a timeout or core dump without failure
        lttd = os.path.basename(last_test_temp_dir)
        failed_dir = os.getenv('FAILED_DIR')
        link_path = '%s%s-FAILED' % (failed_dir, lttd)
        if not os.path.exists(link_path):
            os.symlink(last_test_temp_dir, link_path)
        logger.error("Symlink to failed testcase directory: %s -> %s"
                     % (link_path, lttd))

        # Report core existence
        core_path = get_core_path(last_test_temp_dir)
        if os.path.exists(core_path):
            logger.error(
                "Core-file exists in test temporary directory: %s!" %
                core_path)
            check_core_path(logger, core_path)
            logger.debug("Running 'file %s':" % core_path)
            try:
                info = check_output(["file", core_path])
                logger.debug(info)
            except CalledProcessError as e:
                logger.error("Subprocess returned with return code "
                             "while running `file' utility on core-file "
                             "returned: "
                             "rc=%s", e.returncode)
            except OSError as e:
                logger.error("Subprocess returned with OS error while "
                             "running 'file' utility "
                             "on core-file: "
                             "(%s) %s", e.errno, e.strerror)
            except Exception as e:
                logger.exception("Unexpected error running `file' utility "
                                 "on core-file")

    if vpp_pid:
        # Copy api post mortem
        api_post_mortem_path = "/tmp/api_post_mortem.%d" % vpp_pid
        if os.path.isfile(api_post_mortem_path):
            logger.error("Copying api_post_mortem.%d to %s" %
                         (vpp_pid, last_test_temp_dir))
            shutil.copy2(api_post_mortem_path, last_test_temp_dir)


def check_and_handle_core(vpp_binary, tempdir, core_crash_test):
    if is_core_present(tempdir):
        print('VPP core detected in %s. Last test running was %s' %
              (tempdir, core_crash_test))
        print(single_line_delim)
        spawn_gdb(vpp_binary, get_core_path(tempdir))
        print(single_line_delim)


def handle_cores(failed_testcases):
    if debug_core:
        for failed_testcase in failed_testcases:
            tcs_with_core = failed_testcase.testclasess_with_core
            if tcs_with_core:
                for test, vpp_binary, tempdir in tcs_with_core.values():
                    check_and_handle_core(vpp_binary, tempdir, test)


def process_finished_testsuite(wrapped_testcase_suite,
                               finished_testcase_suites,
                               failed_wrapped_testcases,
                               results):
    results.append(wrapped_testcase_suite.result)
    finished_testcase_suites.add(wrapped_testcase_suite)
    stop_run = False
    if failfast and not wrapped_testcase_suite.was_successful():
        stop_run = True

    if not wrapped_testcase_suite.was_successful():
        failed_wrapped_testcases.add(wrapped_testcase_suite)
        handle_failed_suite(wrapped_testcase_suite.logger,
                            wrapped_testcase_suite.last_test_temp_dir,
                            wrapped_testcase_suite.vpp_pid)

    return stop_run


def run_forked(testcase_suites):
    wrapped_testcase_suites = set()

    # suites are unhashable, need to use list
    results = []
    unread_testcases = set()
    finished_unread_testcases = set()
    manager = StreamQueueManager()
    manager.start()
    for i in range(concurrent_tests):
        if testcase_suites:
            wrapped_testcase_suite = TestCaseWrapper(testcase_suites.pop(0),
                                                     manager)
            wrapped_testcase_suites.add(wrapped_testcase_suite)
            unread_testcases.add(wrapped_testcase_suite)
        else:
            break

    read_from_testcases = threading.Event()
    read_from_testcases.set()
    stdouterr_thread = threading.Thread(target=stdouterr_reader_wrapper,
                                        args=(unread_testcases,
                                              finished_unread_testcases,
                                              read_from_testcases))
    stdouterr_thread.start()

    failed_wrapped_testcases = set()
    stop_run = False

    try:
        while wrapped_testcase_suites:
            finished_testcase_suites = set()
            for wrapped_testcase_suite in wrapped_testcase_suites:
                while wrapped_testcase_suite.result_parent_end.poll():
                    wrapped_testcase_suite.result.process_result(
                        *wrapped_testcase_suite.result_parent_end.recv())
                    wrapped_testcase_suite.last_heard = time.time()

                while wrapped_testcase_suite.keep_alive_parent_end.poll():
                    wrapped_testcase_suite.last_test, \
                        wrapped_testcase_suite.last_test_vpp_binary, \
                        wrapped_testcase_suite.last_test_temp_dir, \
                        wrapped_testcase_suite.vpp_pid = \
                        wrapped_testcase_suite.keep_alive_parent_end.recv()
                    wrapped_testcase_suite.last_heard = time.time()

                if wrapped_testcase_suite.finished_parent_end.poll():
                    wrapped_testcase_suite.finished_parent_end.recv()
                    wrapped_testcase_suite.last_heard = time.time()
                    stop_run = process_finished_testsuite(
                        wrapped_testcase_suite,
                        finished_testcase_suites,
                        failed_wrapped_testcases,
                        results) or stop_run
                    continue

                fail = False
                if wrapped_testcase_suite.last_heard + test_timeout < \
                        time.time():
                    fail = True
                    wrapped_testcase_suite.logger.critical(
                        "Child test runner process timed out "
                        "(last test running was `%s' in `%s')!" %
                        (wrapped_testcase_suite.last_test,
                         wrapped_testcase_suite.last_test_temp_dir))
                elif not wrapped_testcase_suite.child.is_alive():
                    fail = True
                    wrapped_testcase_suite.logger.critical(
                        "Child test runner process unexpectedly died "
                        "(last test running was `%s' in `%s')!" %
                        (wrapped_testcase_suite.last_test,
                         wrapped_testcase_suite.last_test_temp_dir))
                elif wrapped_testcase_suite.last_test_temp_dir and \
                        wrapped_testcase_suite.last_test_vpp_binary:
                    if is_core_present(
                            wrapped_testcase_suite.last_test_temp_dir):
                        wrapped_testcase_suite.add_testclass_with_core()
                        if wrapped_testcase_suite.core_detected_at is None:
                            wrapped_testcase_suite.core_detected_at = \
                                time.time()
                        elif wrapped_testcase_suite.core_detected_at + \
                                core_timeout < time.time():
                            wrapped_testcase_suite.logger.critical(
                                "Child test runner process unresponsive and "
                                "core-file exists in test temporary directory "
                                "(last test running was `%s' in `%s')!" %
                                (wrapped_testcase_suite.last_test,
                                 wrapped_testcase_suite.last_test_temp_dir))
                            fail = True

                if fail:
                    wrapped_testcase_suite.child.terminate()
                    try:
                        # terminating the child process tends to leave orphan
                        # VPP process around
                        if wrapped_testcase_suite.vpp_pid:
                            os.kill(wrapped_testcase_suite.vpp_pid,
                                    signal.SIGTERM)
                    except OSError:
                        # already dead
                        pass
                    wrapped_testcase_suite.result.crashed = True
                    wrapped_testcase_suite.result.process_result(
                        wrapped_testcase_suite.last_test_id, ERROR)
                    stop_run = process_finished_testsuite(
                        wrapped_testcase_suite,
                        finished_testcase_suites,
                        failed_wrapped_testcases,
                        results) or stop_run

            for finished_testcase in finished_testcase_suites:
                finished_testcase.child.join()
                finished_testcase.close_pipes()
                wrapped_testcase_suites.remove(finished_testcase)
                finished_unread_testcases.add(finished_testcase)
                finished_testcase.stdouterr_queue.put(None)
                if stop_run:
                    while testcase_suites:
                        results.append(TestResult(testcase_suites.pop(0)))
                elif testcase_suites:
                    new_testcase = TestCaseWrapper(testcase_suites.pop(0),
                                                   manager)
                    wrapped_testcase_suites.add(new_testcase)
                    unread_testcases.add(new_testcase)
    except Exception:
        for wrapped_testcase_suite in wrapped_testcase_suites:
            wrapped_testcase_suite.child.terminate()
            wrapped_testcase_suite.stdouterr_queue.put(None)
        raise
    finally:
        read_from_testcases.clear()
        stdouterr_thread.join(test_timeout)
        manager.shutdown()

    handle_cores(failed_wrapped_testcases)
    return results


class SplitToSuitesCallback:
    def __init__(self, filter_callback):
        self.suites = {}
        self.suite_name = 'default'
        self.filter_callback = filter_callback
        self.filtered = unittest.TestSuite()

    def __call__(self, file_name, cls, method):
        test_method = cls(method)
        if self.filter_callback(file_name, cls.__name__, method):
            self.suite_name = file_name + cls.__name__
            if self.suite_name not in self.suites:
                self.suites[self.suite_name] = unittest.TestSuite()
            self.suites[self.suite_name].addTest(test_method)

        else:
            self.filtered.addTest(test_method)


test_option = "TEST"


def parse_test_option():
    f = os.getenv(test_option, None)
    filter_file_name = None
    filter_class_name = None
    filter_func_name = None
    if f:
        if '.' in f:
            parts = f.split('.')
            if len(parts) > 3:
                raise Exception("Unrecognized %s option: %s" %
                                (test_option, f))
            if len(parts) > 2:
                if parts[2] not in ('*', ''):
                    filter_func_name = parts[2]
            if parts[1] not in ('*', ''):
                filter_class_name = parts[1]
            if parts[0] not in ('*', ''):
                if parts[0].startswith('test_'):
                    filter_file_name = parts[0]
                else:
                    filter_file_name = 'test_%s' % parts[0]
        else:
            if f.startswith('test_'):
                filter_file_name = f
            else:
                filter_file_name = 'test_%s' % f
    if filter_file_name:
        filter_file_name = '%s.py' % filter_file_name
    return filter_file_name, filter_class_name, filter_func_name


def filter_tests(tests, filter_cb):
    result = unittest.suite.TestSuite()
    for t in tests:
        if isinstance(t, unittest.suite.TestSuite):
            # this is a bunch of tests, recursively filter...
            x = filter_tests(t, filter_cb)
            if x.countTestCases() > 0:
                result.addTest(x)
        elif isinstance(t, unittest.TestCase):
            # this is a single test
            parts = t.id().split('.')
            # t.id() for common cases like this:
            # test_classifier.TestClassifier.test_acl_ip
            # apply filtering only if it is so
            if len(parts) == 3:
                if not filter_cb(parts[0], parts[1], parts[2]):
                    continue
            result.addTest(t)
        else:
            # unexpected object, don't touch it
            result.addTest(t)
    return result


class FilterByTestOption:
    def __init__(self, filter_file_name, filter_class_name, filter_func_name):
        self.filter_file_name = filter_file_name
        self.filter_class_name = filter_class_name
        self.filter_func_name = filter_func_name

    def __call__(self, file_name, class_name, func_name):
        if self.filter_file_name:
            fn_match = fnmatch.fnmatch(file_name, self.filter_file_name)
            if not fn_match:
                return False
        if self.filter_class_name and class_name != self.filter_class_name:
            return False
        if self.filter_func_name and func_name != self.filter_func_name:
            return False
        return True


class FilterByClassList:
    def __init__(self, classes_with_filenames):
        self.classes_with_filenames = classes_with_filenames

    def __call__(self, file_name, class_name, func_name):
        return '.'.join([file_name, class_name]) in self.classes_with_filenames


def suite_from_failed(suite, failed):
    failed = {x.rsplit('.', 1)[0] for x in failed}
    filter_cb = FilterByClassList(failed)
    suite = filter_tests(suite, filter_cb)
    return suite


class AllResults(dict):
    def __init__(self):
        super(AllResults, self).__init__()
        self.all_testcases = 0
        self.results_per_suite = []
        self[PASS] = 0
        self[FAIL] = 0
        self[ERROR] = 0
        self[SKIP] = 0
        self[TEST_RUN] = 0
        self.rerun = []
        self.testsuites_no_tests_run = []

    def add_results(self, result):
        self.results_per_suite.append(result)
        result_types = [PASS, FAIL, ERROR, SKIP, TEST_RUN]
        for result_type in result_types:
            self[result_type] += len(result[result_type])

    def add_result(self, result):
        retval = 0
        self.all_testcases += result.testcase_suite.countTestCases()
        self.add_results(result)

        if result.no_tests_run():
            self.testsuites_no_tests_run.append(result.testcase_suite)
            if result.crashed:
                retval = -1
            else:
                retval = 1
        elif not result.was_successful():
            retval = 1

        if retval != 0:
            self.rerun.append(result.testcase_suite)

        return retval

    def print_results(self):
        print('')
        print(double_line_delim)
        print('TEST RESULTS:')
        print('     Scheduled tests: {}'.format(self.all_testcases))
        print('      Executed tests: {}'.format(self[TEST_RUN]))
        print('        Passed tests: {}'.format(
            colorize(str(self[PASS]), GREEN)))
        if self[SKIP] > 0:
            print('       Skipped tests: {}'.format(
                colorize(str(self[SKIP]), YELLOW)))
        if self.not_executed > 0:
            print('  Not Executed tests: {}'.format(
                colorize(str(self.not_executed), RED)))
        if self[FAIL] > 0:
            print('            Failures: {}'.format(
                colorize(str(self[FAIL]), RED)))
        if self[ERROR] > 0:
            print('              Errors: {}'.format(
                colorize(str(self[ERROR]), RED)))

        if self.all_failed > 0:
            print('FAILURES AND ERRORS IN TESTS:')
            for result in self.results_per_suite:
                failed_testcase_ids = result[FAIL]
                errored_testcase_ids = result[ERROR]
                old_testcase_name = None
                if failed_testcase_ids or errored_testcase_ids:
                    for failed_test_id in failed_testcase_ids:
                        new_testcase_name, test_name = \
                            result.get_testcase_names(failed_test_id)
                        if new_testcase_name != old_testcase_name:
                            print('  Testcase name: {}'.format(
                                colorize(new_testcase_name, RED)))
                            old_testcase_name = new_testcase_name
                        print('    FAILURE: {} [{}]'.format(
                            colorize(test_name, RED), failed_test_id))
                    for failed_test_id in errored_testcase_ids:
                        new_testcase_name, test_name = \
                            result.get_testcase_names(failed_test_id)
                        if new_testcase_name != old_testcase_name:
                            print('  Testcase name: {}'.format(
                                colorize(new_testcase_name, RED)))
                            old_testcase_name = new_testcase_name
                        print('      ERROR: {} [{}]'.format(
                            colorize(test_name, RED), failed_test_id))
        if self.testsuites_no_tests_run:
            print('TESTCASES WHERE NO TESTS WERE SUCCESSFULLY EXECUTED:')
            tc_classes = set()
            for testsuite in self.testsuites_no_tests_run:
                for testcase in testsuite:
                    tc_classes.add(get_testcase_doc_name(testcase))
            for tc_class in tc_classes:
                print('  {}'.format(colorize(tc_class, RED)))

        print(double_line_delim)
        print('')

    @property
    def not_executed(self):
        return self.all_testcases - self[TEST_RUN]

    @property
    def all_failed(self):
        return self[FAIL] + self[ERROR]


def parse_results(results):
    """
    Prints the number of scheduled, executed, not executed, passed, failed,
    errored and skipped tests and details about failed and errored tests.

    Also returns all suites where any test failed.

    :param results:
    :return:
    """

    results_per_suite = AllResults()
    crashed = False
    failed = False
    for result in results:
        result_code = results_per_suite.add_result(result)
        if result_code == 1:
            failed = True
        elif result_code == -1:
            crashed = True

    results_per_suite.print_results()

    if crashed:
        return_code = -1
    elif failed:
        return_code = 1
    else:
        return_code = 0
    return return_code, results_per_suite.rerun


def parse_digit_env(env_var, default):
    value = os.getenv(env_var, default)
    if value != default:
        if value.isdigit():
            value = int(value)
        else:
            print('WARNING: unsupported value "%s" for env var "%s",'
                  'defaulting to %s' % (value, env_var, default))
            value = default
    return value


if __name__ == '__main__':

    verbose = parse_digit_env("V", 0)

    test_timeout = parse_digit_env("TIMEOUT", 600)  # default = 10 minutes

    retries = parse_digit_env("RETRIES", 0)

    debug = os.getenv("DEBUG", "n").lower() in ["gdb", "gdbserver"]

    debug_core = os.getenv("DEBUG", "").lower() == "core"

    step = os.getenv("STEP", "n").lower() in ("y", "yes", "1")

    run_interactive = debug or step

    test_jobs = os.getenv("TEST_JOBS", "1").lower()  # default = 1 process
    if test_jobs == 'auto':
        if run_interactive:
            concurrent_tests = 1
            print('Interactive mode required, running on one core')
        else:
            shm_free = psutil.disk_usage('/dev/shm').free
            shm_max_processes = 1
            if shm_free < min_req_shm:
                raise Exception('Not enough free space in /dev/shm. Required '
                                'free space is at least %sM.'
                                % (min_req_shm >> 20))
            else:
                extra_shm = shm_free - min_req_shm
                shm_max_processes += extra_shm / shm_per_process
            concurrent_tests = min(cpu_count(), shm_max_processes)
            print('Found enough resources to run tests with %s cores'
                  % concurrent_tests)
    elif test_jobs.isdigit():
        concurrent_tests = int(test_jobs)
    else:
        concurrent_tests = 1

    if run_interactive and concurrent_tests > 1:
        raise NotImplementedError(
            'Running tests interactively (DEBUG is gdb or gdbserver or STEP '
            'is set) in parallel (TEST_JOBS is more than 1) is not supported')

    parser = argparse.ArgumentParser(description="VPP unit tests")
    parser.add_argument("-f", "--failfast", action='store_true',
                        help="fast failure flag")
    parser.add_argument("-d", "--dir", action='append', type=str,
                        help="directory containing test files "
                             "(may be specified multiple times)")
    args = parser.parse_args()
    failfast = args.failfast
    descriptions = True

    print("Running tests using custom test runner")  # debug message
    filter_file, filter_class, filter_func = parse_test_option()

    print("Active filters: file=%s, class=%s, function=%s" % (
        filter_file, filter_class, filter_func))

    filter_cb = FilterByTestOption(filter_file, filter_class, filter_func)

    ignore_path = os.getenv("VENV_PATH", None)
    cb = SplitToSuitesCallback(filter_cb)
    for d in args.dir:
        print("Adding tests from directory tree %s" % d)
        discover_tests(d, cb, ignore_path)

    # suites are not hashable, need to use list
    suites = []
    tests_amount = 0
    for testcase_suite in cb.suites.values():
        tests_amount += testcase_suite.countTestCases()
        suites.append(testcase_suite)

    print("%s out of %s tests match specified filters" % (
        tests_amount, tests_amount + cb.filtered.countTestCases()))

    if not running_extended_tests:
        print("Not running extended tests (some tests will be skipped)")

    attempts = retries + 1
    if attempts > 1:
        print("Perform %s attempts to pass the suite..." % attempts)

    if run_interactive and suites:
        # don't fork if requiring interactive terminal
        full_suite = unittest.TestSuite()
        map(full_suite.addTests, suites)
        result = VppTestRunner(verbosity=verbose,
                               failfast=failfast,
                               print_summary=True).run(full_suite)
        was_successful = result.wasSuccessful()
        if not was_successful:
            for test_case_info in result.failed_test_cases_info:
                handle_failed_suite(test_case_info.logger,
                                    test_case_info.tempdir,
                                    test_case_info.vpp_pid)
                if debug_core and \
                        test_case_info in result.core_crash_test_cases_info:
                    check_and_handle_core(test_case_info.vpp_bin_path,
                                          test_case_info.tempdir,
                                          test_case_info.core_crash_test)

        sys.exit(not was_successful)
    else:
        exit_code = 0
        while suites and attempts > 0:
            results = run_forked(suites)
            exit_code, suites = parse_results(results)
            attempts -= 1
            if exit_code == 0:
                print('Test run was successful')
            else:
                print('%s attempt(s) left.' % attempts)
        sys.exit(exit_code)