/mandos/trunk

#!/usr/bin/python
# -*- mode: python; coding: utf-8; after-save-hook: (lambda () (let ((command (if (and (boundp 'tramp-file-name-structure) (string-match (car tramp-file-name-structure) (buffer-file-name))) (tramp-file-name-localname (tramp-dissect-file-name (buffer-file-name))) (buffer-file-name)))) (if (= (shell-command (format "%s --check" (shell-quote-argument command)) "*Test*") 0) (let ((w (get-buffer-window "*Test*"))) (if w (delete-window w)) (kill-buffer "*Test*")) (display-buffer "*Test*")))); -*-
#
# Mandos Monitor - Control and monitor the Mandos server
#
# Copyright © 2008-2019 Teddy Hogeborn
# Copyright © 2008-2019 Björn Påhlsson
#
# This file is part of Mandos.
#
# Mandos is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
#     Mandos is distributed in the hope that it will be useful, but
#     WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#     GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Mandos.  If not, see <http://www.gnu.org/licenses/>.
#
# Contact the authors at <mandos@recompile.se>.
#

from __future__ import (division, absolute_import, print_function,
                        unicode_literals)

try:
    from future_builtins import *
except ImportError:
    pass

import sys
import argparse
import locale
import datetime
import re
import os
import collections
import json
import unittest
import logging

import dbus

# Show warnings by default
if not sys.warnoptions:
    import warnings
    warnings.simplefilter("default")

log = logging.getLogger(sys.argv[0])
logging.basicConfig(level="INFO", # Show info level messages
                    format="%(message)s") # Show basic log messages

logging.captureWarnings(True)   # Show warnings via the logging system

if sys.version_info.major == 2:
    str = unicode

locale.setlocale(locale.LC_ALL, "")

defaultkeywords = ("Name", "Enabled", "Timeout", "LastCheckedOK")
domain = "se.recompile"
busname = domain + ".Mandos"
server_path = "/"
server_interface = domain + ".Mandos"
client_interface = domain + ".Mandos.Client"
version = "1.8.3"


try:
    dbus.OBJECT_MANAGER_IFACE
except AttributeError:
    dbus.OBJECT_MANAGER_IFACE = "org.freedesktop.DBus.ObjectManager"


def milliseconds_to_string(ms):
    td = datetime.timedelta(0, 0, 0, ms)
    return ("{days}{hours:02}:{minutes:02}:{seconds:02}"
            .format(days="{}T".format(td.days) if td.days else "",
                    hours=td.seconds // 3600,
                    minutes=(td.seconds % 3600) // 60,
                    seconds=td.seconds % 60))


def rfc3339_duration_to_delta(duration):
    """Parse an RFC 3339 "duration" and return a datetime.timedelta

    >>> rfc3339_duration_to_delta("P7D")
    datetime.timedelta(7)
    >>> rfc3339_duration_to_delta("PT60S")
    datetime.timedelta(0, 60)
    >>> rfc3339_duration_to_delta("PT60M")
    datetime.timedelta(0, 3600)
    >>> rfc3339_duration_to_delta("P60M")
    datetime.timedelta(1680)
    >>> rfc3339_duration_to_delta("PT24H")
    datetime.timedelta(1)
    >>> rfc3339_duration_to_delta("P1W")
    datetime.timedelta(7)
    >>> rfc3339_duration_to_delta("PT5M30S")
    datetime.timedelta(0, 330)
    >>> rfc3339_duration_to_delta("P1DT3M20S")
    datetime.timedelta(1, 200)
    >>> # Can not be empty:
    >>> rfc3339_duration_to_delta("")
    Traceback (most recent call last):
    ...
    ValueError: Invalid RFC 3339 duration: u''
    >>> # Must start with "P":
    >>> rfc3339_duration_to_delta("1D")
    Traceback (most recent call last):
    ...
    ValueError: Invalid RFC 3339 duration: u'1D'
    >>> # Must use correct order
    >>> rfc3339_duration_to_delta("PT1S2M")
    Traceback (most recent call last):
    ...
    ValueError: Invalid RFC 3339 duration: u'PT1S2M'
    >>> # Time needs time marker
    >>> rfc3339_duration_to_delta("P1H2S")
    Traceback (most recent call last):
    ...
    ValueError: Invalid RFC 3339 duration: u'P1H2S'
    >>> # Weeks can not be combined with anything else
    >>> rfc3339_duration_to_delta("P1D2W")
    Traceback (most recent call last):
    ...
    ValueError: Invalid RFC 3339 duration: u'P1D2W'
    >>> rfc3339_duration_to_delta("P2W2H")
    Traceback (most recent call last):
    ...
    ValueError: Invalid RFC 3339 duration: u'P2W2H'
    """

    # Parsing an RFC 3339 duration with regular expressions is not
    # possible - there would have to be multiple places for the same
    # values, like seconds.  The current code, while more esoteric, is
    # cleaner without depending on a parsing library.  If Python had a
    # built-in library for parsing we would use it, but we'd like to
    # avoid excessive use of external libraries.

    # New type for defining tokens, syntax, and semantics all-in-one
    Token = collections.namedtuple("Token", (
        "regexp",  # To match token; if "value" is not None, must have
                   # a "group" containing digits
        "value",   # datetime.timedelta or None
        "followers"))           # Tokens valid after this token
    # RFC 3339 "duration" tokens, syntax, and semantics; taken from
    # the "duration" ABNF definition in RFC 3339, Appendix A.
    token_end = Token(re.compile(r"$"), None, frozenset())
    token_second = Token(re.compile(r"(\d+)S"),
                         datetime.timedelta(seconds=1),
                         frozenset((token_end, )))
    token_minute = Token(re.compile(r"(\d+)M"),
                         datetime.timedelta(minutes=1),
                         frozenset((token_second, token_end)))
    token_hour = Token(re.compile(r"(\d+)H"),
                       datetime.timedelta(hours=1),
                       frozenset((token_minute, token_end)))
    token_time = Token(re.compile(r"T"),
                       None,
                       frozenset((token_hour, token_minute,
                                  token_second)))
    token_day = Token(re.compile(r"(\d+)D"),
                      datetime.timedelta(days=1),
                      frozenset((token_time, token_end)))
    token_month = Token(re.compile(r"(\d+)M"),
                        datetime.timedelta(weeks=4),
                        frozenset((token_day, token_end)))
    token_year = Token(re.compile(r"(\d+)Y"),
                       datetime.timedelta(weeks=52),
                       frozenset((token_month, token_end)))
    token_week = Token(re.compile(r"(\d+)W"),
                       datetime.timedelta(weeks=1),
                       frozenset((token_end, )))
    token_duration = Token(re.compile(r"P"), None,
                           frozenset((token_year, token_month,
                                      token_day, token_time,
                                      token_week)))
    # Define starting values:
    # Value so far
    value = datetime.timedelta()
    found_token = None
    # Following valid tokens
    followers = frozenset((token_duration, ))
    # String left to parse
    s = duration
    # Loop until end token is found
    while found_token is not token_end:
        # Search for any currently valid tokens
        for token in followers:
            match = token.regexp.match(s)
            if match is not None:
                # Token found
                if token.value is not None:
                    # Value found, parse digits
                    factor = int(match.group(1), 10)
                    # Add to value so far
                    value += factor * token.value
                # Strip token from string
                s = token.regexp.sub("", s, 1)
                # Go to found token
                found_token = token
                # Set valid next tokens
                followers = found_token.followers
                break
        else:
            # No currently valid tokens were found
            raise ValueError("Invalid RFC 3339 duration: {!r}"
                             .format(duration))
    # End token found
    return value


def string_to_delta(interval):
    """Parse a string and return a datetime.timedelta
    """

    try:
        return rfc3339_duration_to_delta(interval)
    except ValueError as e:
        log.warning("%s - Parsing as pre-1.6.1 interval instead",
                    ' '.join(e.args))
    return parse_pre_1_6_1_interval(interval)


def parse_pre_1_6_1_interval(interval):
    """Parse an interval string as documented by Mandos before 1.6.1, and
    return a datetime.timedelta
    >>> parse_pre_1_6_1_interval('7d')
    datetime.timedelta(7)
    >>> parse_pre_1_6_1_interval('60s')
    datetime.timedelta(0, 60)
    >>> parse_pre_1_6_1_interval('60m')
    datetime.timedelta(0, 3600)
    >>> parse_pre_1_6_1_interval('24h')
    datetime.timedelta(1)
    >>> parse_pre_1_6_1_interval('1w')
    datetime.timedelta(7)
    >>> parse_pre_1_6_1_interval('5m 30s')
    datetime.timedelta(0, 330)
    >>> parse_pre_1_6_1_interval('')
    datetime.timedelta(0)
    >>> # Ignore unknown characters, allow any order and repetitions
    >>> parse_pre_1_6_1_interval('2dxy7zz11y3m5m')
    datetime.timedelta(2, 480, 18000)

    """

    value = datetime.timedelta(0)
    regexp = re.compile(r"(\d+)([dsmhw]?)")

    for num, suffix in regexp.findall(interval):
        if suffix == "d":
            value += datetime.timedelta(int(num))
        elif suffix == "s":
            value += datetime.timedelta(0, int(num))
        elif suffix == "m":
            value += datetime.timedelta(0, 0, 0, 0, int(num))
        elif suffix == "h":
            value += datetime.timedelta(0, 0, 0, 0, 0, int(num))
        elif suffix == "w":
            value += datetime.timedelta(0, 0, 0, 0, 0, 0, int(num))
        elif suffix == "":
            value += datetime.timedelta(0, 0, 0, int(num))
    return value


class TableOfClients(object):
    tablewords = {
        "Name": "Name",
        "Enabled": "Enabled",
        "Timeout": "Timeout",
        "LastCheckedOK": "Last Successful Check",
        "LastApprovalRequest": "Last Approval Request",
        "Created": "Created",
        "Interval": "Interval",
        "Host": "Host",
        "Fingerprint": "Fingerprint",
        "KeyID": "Key ID",
        "CheckerRunning": "Check Is Running",
        "LastEnabled": "Last Enabled",
        "ApprovalPending": "Approval Is Pending",
        "ApprovedByDefault": "Approved By Default",
        "ApprovalDelay": "Approval Delay",
        "ApprovalDuration": "Approval Duration",
        "Checker": "Checker",
        "ExtendedTimeout": "Extended Timeout",
        "Expires": "Expires",
        "LastCheckerStatus": "Last Checker Status",
    }

    def __init__(self, clients, keywords, tablewords=None):
        self.clients = clients
        self.keywords = keywords
        if tablewords is not None:
            self.tablewords = tablewords

    def __str__(self):
        return "\n".join(self.rows())

    if sys.version_info.major == 2:
        __unicode__ = __str__
        def __str__(self):
            return str(self).encode(locale.getpreferredencoding())

    def rows(self):
        format_string = self.row_formatting_string()
        rows = [self.header_line(format_string)]
        rows.extend(self.client_line(client, format_string)
                    for client in self.clients)
        return rows

    def row_formatting_string(self):
        "Format string used to format table rows"
        return " ".join("{{{key}:{width}}}".format(
            width=max(len(self.tablewords[key]),
                      max(len(self.string_from_client(client, key))
                          for client in self.clients)),
            key=key)
                                 for key in self.keywords)

    def string_from_client(self, client, key):
        return self.valuetostring(client[key], key)

    @staticmethod
    def valuetostring(value, keyword):
        if isinstance(value, dbus.Boolean):
            return "Yes" if value else "No"
        if keyword in ("Timeout", "Interval", "ApprovalDelay",
                       "ApprovalDuration", "ExtendedTimeout"):
            return milliseconds_to_string(value)
        return str(value)

    def header_line(self, format_string):
        return format_string.format(**self.tablewords)

    def client_line(self, client, format_string):
        return format_string.format(
            **{key: self.string_from_client(client, key)
               for key in self.keywords})


def has_actions(options):
    return any((options.enable,
                options.disable,
                options.bump_timeout,
                options.start_checker,
                options.stop_checker,
                options.is_enabled,
                options.remove,
                options.checker is not None,
                options.timeout is not None,
                options.extended_timeout is not None,
                options.interval is not None,
                options.approved_by_default is not None,
                options.approval_delay is not None,
                options.approval_duration is not None,
                options.host is not None,
                options.secret is not None,
                options.approve,
                options.deny))


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--version", action="version",
                        version="%(prog)s {}".format(version),
                        help="show version number and exit")
    parser.add_argument("-a", "--all", action="store_true",
                        help="Select all clients")
    parser.add_argument("-v", "--verbose", action="store_true",
                        help="Print all fields")
    parser.add_argument("-j", "--dump-json", action="store_true",
                        help="Dump client data in JSON format")
    parser.add_argument("-e", "--enable", action="store_true",
                        help="Enable client")
    parser.add_argument("-d", "--disable", action="store_true",
                        help="disable client")
    parser.add_argument("-b", "--bump-timeout", action="store_true",
                        help="Bump timeout for client")
    parser.add_argument("--start-checker", action="store_true",
                        help="Start checker for client")
    parser.add_argument("--stop-checker", action="store_true",
                        help="Stop checker for client")
    parser.add_argument("-V", "--is-enabled", action="store_true",
                        help="Check if client is enabled")
    parser.add_argument("-r", "--remove", action="store_true",
                        help="Remove client")
    parser.add_argument("-c", "--checker",
                        help="Set checker command for client")
    parser.add_argument("-t", "--timeout",
                        help="Set timeout for client")
    parser.add_argument("--extended-timeout",
                        help="Set extended timeout for client")
    parser.add_argument("-i", "--interval",
                        help="Set checker interval for client")
    parser.add_argument("--approve-by-default", action="store_true",
                        default=None, dest="approved_by_default",
                        help="Set client to be approved by default")
    parser.add_argument("--deny-by-default", action="store_false",
                        dest="approved_by_default",
                        help="Set client to be denied by default")
    parser.add_argument("--approval-delay",
                        help="Set delay before client approve/deny")
    parser.add_argument("--approval-duration",
                        help="Set duration of one client approval")
    parser.add_argument("-H", "--host", help="Set host for client")
    parser.add_argument("-s", "--secret",
                        type=argparse.FileType(mode="rb"),
                        help="Set password blob (file) for client")
    parser.add_argument("-A", "--approve", action="store_true",
                        help="Approve any current client request")
    parser.add_argument("-D", "--deny", action="store_true",
                        help="Deny any current client request")
    parser.add_argument("--check", action="store_true",
                        help="Run self-test")
    parser.add_argument("client", nargs="*", help="Client name")
    options = parser.parse_args()

    if has_actions(options) and not (options.client or options.all):
        parser.error("Options require clients names or --all.")
    if options.verbose and has_actions(options):
        parser.error("--verbose can only be used alone.")
    if options.dump_json and (options.verbose
                              or has_actions(options)):
        parser.error("--dump-json can only be used alone.")
    if options.all and not has_actions(options):
        parser.error("--all requires an action.")

    try:
        bus = dbus.SystemBus()
        mandos_dbus_objc = bus.get_object(busname, server_path)
    except dbus.exceptions.DBusException:
        log.critical("Could not connect to Mandos server")
        sys.exit(1)

    mandos_serv = dbus.Interface(mandos_dbus_objc,
                                 dbus_interface=server_interface)
    mandos_serv_object_manager = dbus.Interface(
        mandos_dbus_objc, dbus_interface=dbus.OBJECT_MANAGER_IFACE)

    # block stderr since dbus library prints to stderr
    null = os.open(os.path.devnull, os.O_RDWR)
    stderrcopy = os.dup(sys.stderr.fileno())
    os.dup2(null, sys.stderr.fileno())
    os.close(null)
    try:
        try:
            mandos_clients = {path: ifs_and_props[client_interface]
                              for path, ifs_and_props in
                              mandos_serv_object_manager
                              .GetManagedObjects().items()
                              if client_interface in ifs_and_props}
        finally:
            # restore stderr
            os.dup2(stderrcopy, sys.stderr.fileno())
            os.close(stderrcopy)
    except dbus.exceptions.DBusException as e:
        log.critical("Failed to access Mandos server through D-Bus:"
                     "\n%s", e)
        sys.exit(1)

    # Compile dict of (clients: properties) to process
    clients = {}

    if options.all or not options.client:
        clients = {bus.get_object(busname, path): properties
                   for path, properties in mandos_clients.items()}
    else:
        for name in options.client:
            for path, client in mandos_clients.items():
                if client["Name"] == name:
                    client_objc = bus.get_object(busname, path)
                    clients[client_objc] = client
                    break
            else:
                log.critical("Client not found on server: %r", name)
                sys.exit(1)

    if not has_actions(options) and clients:
        if options.verbose or options.dump_json:
            keywords = ("Name", "Enabled", "Timeout", "LastCheckedOK",
                        "Created", "Interval", "Host", "KeyID",
                        "Fingerprint", "CheckerRunning",
                        "LastEnabled", "ApprovalPending",
                        "ApprovedByDefault", "LastApprovalRequest",
                        "ApprovalDelay", "ApprovalDuration",
                        "Checker", "ExtendedTimeout", "Expires",
                        "LastCheckerStatus")
        else:
            keywords = defaultkeywords

        if options.dump_json:
            json.dump({client["Name"]: {key:
                                        bool(client[key])
                                        if isinstance(client[key],
                                                      dbus.Boolean)
                                        else client[key]
                                        for key in keywords}
                       for client in clients.values()},
                      fp=sys.stdout, indent=4,
                      separators=(',', ': '))
            print()
        else:
            print(TableOfClients(clients.values(), keywords))
    else:
        # Process each client in the list by all selected options
        for client in clients:

            def set_client_prop(prop, value):
                """Set a Client D-Bus property"""
                client.Set(client_interface, prop, value,
                           dbus_interface=dbus.PROPERTIES_IFACE)

            def set_client_prop_ms(prop, value):
                """Set a Client D-Bus property, converted
                from a string to milliseconds."""
                set_client_prop(prop,
                                string_to_delta(value).total_seconds()
                                * 1000)

            if options.remove:
                mandos_serv.RemoveClient(client.__dbus_object_path__)
            if options.enable:
                set_client_prop("Enabled", dbus.Boolean(True))
            if options.disable:
                set_client_prop("Enabled", dbus.Boolean(False))
            if options.bump_timeout:
                set_client_prop("LastCheckedOK", "")
            if options.start_checker:
                set_client_prop("CheckerRunning", dbus.Boolean(True))
            if options.stop_checker:
                set_client_prop("CheckerRunning", dbus.Boolean(False))
            if options.is_enabled:
                if client.Get(client_interface, "Enabled",
                              dbus_interface=dbus.PROPERTIES_IFACE):
                    sys.exit(0)
                else:
                    sys.exit(1)
            if options.checker is not None:
                set_client_prop("Checker", options.checker)
            if options.host is not None:
                set_client_prop("Host", options.host)
            if options.interval is not None:
                set_client_prop_ms("Interval", options.interval)
            if options.approval_delay is not None:
                set_client_prop_ms("ApprovalDelay",
                                   options.approval_delay)
            if options.approval_duration is not None:
                set_client_prop_ms("ApprovalDuration",
                                   options.approval_duration)
            if options.timeout is not None:
                set_client_prop_ms("Timeout", options.timeout)
            if options.extended_timeout is not None:
                set_client_prop_ms("ExtendedTimeout",
                                   options.extended_timeout)
            if options.secret is not None:
                set_client_prop("Secret",
                                dbus.ByteArray(options.secret.read()))
            if options.approved_by_default is not None:
                set_client_prop("ApprovedByDefault",
                                dbus.Boolean(options
                                             .approved_by_default))
            if options.approve:
                client.Approve(dbus.Boolean(True),
                               dbus_interface=client_interface)
            elif options.deny:
                client.Approve(dbus.Boolean(False),
                               dbus_interface=client_interface)


class Test_milliseconds_to_string(unittest.TestCase):
    def test_all(self):
        self.assertEqual(milliseconds_to_string(93785000),
                         "1T02:03:05")
    def test_no_days(self):
        self.assertEqual(milliseconds_to_string(7385000), "02:03:05")
    def test_all_zero(self):
        self.assertEqual(milliseconds_to_string(0), "00:00:00")
    def test_no_fractional_seconds(self):
        self.assertEqual(milliseconds_to_string(400), "00:00:00")
        self.assertEqual(milliseconds_to_string(900), "00:00:00")
        self.assertEqual(milliseconds_to_string(1900), "00:00:01")

class Test_string_to_delta(unittest.TestCase):
    def test_handles_basic_rfc3339(self):
        self.assertEqual(string_to_delta("PT2H"),
                         datetime.timedelta(0, 7200))
    def test_falls_back_to_pre_1_6_1_with_warning(self):
        # assertLogs only exists in Python 3.4
        if hasattr(self, "assertLogs"):
            with self.assertLogs(log, logging.WARNING):
                value = string_to_delta("2h")
        else:
            value = string_to_delta("2h")
        self.assertEqual(value, datetime.timedelta(0, 7200))

class Test_TableOfClients(unittest.TestCase):
    def setUp(self):
        self.tablewords = {
            "Attr1": "X",
            "AttrTwo": "Yy",
            "AttrThree": "Zzz",
            "Bool": "A D-BUS Boolean",
            "NonDbusBoolean": "A Non-D-BUS Boolean",
            "Integer": "An Integer",
            "Timeout": "Timedelta 1",
            "Interval": "Timedelta 2",
            "ApprovalDelay": "Timedelta 3",
            "ApprovalDuration": "Timedelta 4",
            "ExtendedTimeout": "Timedelta 5",
            "String": "A String",
        }
        self.keywords = ["Attr1", "AttrTwo"]
        self.clients = [
            {
                "Attr1": "x1",
                "AttrTwo": "y1",
                "AttrThree": "z1",
                "Bool": dbus.Boolean(False),
                "NonDbusBoolean": False,
                "Integer": 0,
                "Timeout": 0,
                "Interval": 1000,
                "ApprovalDelay": 2000,
                "ApprovalDuration": 3000,
                "ExtendedTimeout": 4000,
                "String": "",
            },
            {
                "Attr1": "x2",
                "AttrTwo": "y2",
                "AttrThree": "z2",
                "Bool": dbus.Boolean(True),
                "NonDbusBoolean": True,
                "Integer": 1,
                "Timeout": 93785000,
                "Interval": 93786000,
                "ApprovalDelay": 93787000,
                "ApprovalDuration": 93788000,
                "ExtendedTimeout": 93789000,
                "String": "A huge string which will not fit," * 10,
            },
        ]
    def test_short_header(self):
        rows = TableOfClients(self.clients, self.keywords,
                              self.tablewords).rows()
        expected_rows = [
            "X  Yy",
            "x1 y1",
            "x2 y2"]
        self.assertEqual(rows, expected_rows)
    def test_booleans(self):
        keywords = ["Bool", "NonDbusBoolean"]
        rows = TableOfClients(self.clients, keywords,
                              self.tablewords).rows()
        expected_rows = [
            "A D-BUS Boolean A Non-D-BUS Boolean",
            "No              False              ",
            "Yes             True               ",
        ]
        self.assertEqual(rows, expected_rows)
    def test_milliseconds_detection(self):
        keywords = ["Integer", "Timeout", "Interval", "ApprovalDelay",
                    "ApprovalDuration", "ExtendedTimeout"]
        rows = TableOfClients(self.clients, keywords,
                              self.tablewords).rows()
        expected_rows = ("""
An Integer Timedelta 1 Timedelta 2 Timedelta 3 Timedelta 4 Timedelta 5
0          00:00:00    00:00:01    00:00:02    00:00:03    00:00:04   
1          1T02:03:05  1T02:03:06  1T02:03:07  1T02:03:08  1T02:03:09 
"""
        ).splitlines()[1:]
        self.assertEqual(rows, expected_rows)
    def test_empty_and_long_string_values(self):
        keywords = ["String"]
        rows = TableOfClients(self.clients, keywords,
                              self.tablewords).rows()
        expected_rows = ("""
A String                                                                                                                                                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                                                                                          
A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,A huge string which will not fit,
"""
        ).splitlines()[1:]
        self.assertEqual(rows, expected_rows)



def should_only_run_tests():
    parser = argparse.ArgumentParser(add_help=False)
    parser.add_argument("--check", action='store_true')
    args, unknown_args = parser.parse_known_args()
    run_tests = args.check
    if run_tests:
        # Remove --check argument from sys.argv
        sys.argv[1:] = unknown_args
    return run_tests

# Add all tests from doctest strings
def load_tests(loader, tests, none):
    import doctest
    tests.addTests(doctest.DocTestSuite())
    return tests

if __name__ == "__main__":
    if should_only_run_tests():
        # Call using ./tdd-python-script --check [--verbose]
        unittest.main()
    else:
        main()