Adding upstream version 5.3.1.upstream/5.3.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 1983 insertions, 0 deletions

diff --git a/tests/integration/deckard/pydnstest/__init__.py b/tests/integration/deckard/pydnstest/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/__init__.py
diff --git a/tests/integration/deckard/pydnstest/augwrap.py b/tests/integration/deckard/pydnstest/augwrap.py
new file mode 100644
index 0000000..a0ec190
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/augwrap.py
@@ -0,0 +1,226 @@
+#!/usr/bin/python3
+
+# Copyright (C) 2017
+
+import collections.abc
+import logging
+import os  # requires posix
+
+from augeas import Augeas
+
+AUGEAS_LOAD_PATH = '/augeas/load/'
+AUGEAS_FILES_PATH = '/files/'
+AUGEAS_ERROR_PATH = '//error'
+
+log = logging.getLogger('augeas')
+
+
+def join(*paths):
+    """
+    join two Augeas tree paths
+
+    FIXME: Beware: // is normalized to /
+    """
+    norm_paths = [os.path.normpath(path) for path in paths]
+    # first path must be absolute
+    assert norm_paths[0][0] == '/'
+    new_paths = [norm_paths[0]]
+    # relativize all other paths so join works as expected
+    for path in norm_paths[1:]:
+        if path.startswith('/'):
+            path = path[1:]
+        new_paths.append(path)
+    new_path = os.path.join(*new_paths)
+    log.debug("join: new_path %s", new_path)
+    return os.path.normpath(new_path)
+
+
+class AugeasWrapper:
+    """python-augeas higher-level wrapper.
+
+    Load single augeas lens and configuration file.
+    Exposes configuration file as AugeasNode object with dict-like interface.
+
+    AugeasWrapper can be used in with statement in the same way as file does.
+    """
+
+    def __init__(self, confpath, lens, root=None, loadpath=None,
+                 flags=Augeas.NO_MODL_AUTOLOAD | Augeas.NO_LOAD | Augeas.ENABLE_SPAN):
+        """Parse configuration file using given lens.
+
+        Params:
+            confpath (str): Absolute path to the configuration file
+            lens (str): Name of module containing Augeas lens
+            root: passed down to original Augeas
+            flags: passed down to original Augeas
+            loadpath: passed down to original Augeas
+            flags: passed down to original Augeas
+        """
+        log.debug('loadpath: %s', loadpath)
+        log.debug('confpath: %s', confpath)
+        self._aug = Augeas(root=root, loadpath=loadpath, flags=flags)
+
+        # /augeas/load/{lens}
+        aug_load_path = join(AUGEAS_LOAD_PATH, lens)
+        # /augeas/load/{lens}/lens = {lens}.lns
+        self._aug.set(join(aug_load_path, 'lens'), '%s.lns' % lens)
+        # /augeas/load/{lens}/incl[0] = {confpath}
+        self._aug.set(join(aug_load_path, 'incl[0]'), confpath)
+        self._aug.load()
+
+        errors = self._aug.match(AUGEAS_ERROR_PATH)
+        if errors:
+            err_msg = '\n'.join(
+                ["{}: {}".format(e, self._aug.get(e)) for e in errors]
+            )
+            raise RuntimeError(err_msg)
+
+        path = join(AUGEAS_FILES_PATH, confpath)
+        paths = self._aug.match(path)
+        if len(paths) != 1:
+            raise ValueError('path %s did not match exactly once' % path)
+        self.tree = AugeasNode(self._aug, path)
+        self._loaded = True
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.save()
+        self.close()
+
+    def save(self):
+        """Save Augeas tree to its original file."""
+        assert self._loaded
+        try:
+            self._aug.save()
+        except IOError as exc:
+            log.exception(exc)
+            for err_path in self._aug.match('//error'):
+                log.error('%s: %s', err_path,
+                          self._aug.get(os.path.join(err_path, 'message')))
+            raise
+
+    def close(self):
+        """
+        close Augeas library
+
+        After calling close() the object must not be used anymore.
+        """
+        assert self._loaded
+        self._aug.close()
+        del self._aug
+        self._loaded = False
+
+    def match(self, path):
+        """Yield AugeasNodes matching given expression."""
+        assert self._loaded
+        assert path
+        log.debug('tree match %s', path)
+        for matched_path in self._aug.match(path):
+            yield AugeasNode(self._aug, matched_path)
+
+
+class AugeasNode(collections.abc.MutableMapping):
+    """One Augeas tree node with dict-like interface."""
+
+    def __init__(self, aug, path):
+        """
+        Args:
+            aug (AugeasWrapper or Augeas): Augeas library instance
+            path (str): absolute path in Augeas tree matching single node
+
+        BEWARE: There are no sanity checks of given path for performance reasons.
+        """
+        assert aug
+        assert path
+        assert path.startswith('/')
+        self._aug = aug
+        self._path = path
+        self._span = None
+
+    @property
+    def path(self):
+        """canonical path in Augeas tree, read-only"""
+        return self._path
+
+    @property
+    def value(self):
+        """
+        get value of this node in Augeas tree
+        """
+        value = self._aug.get(self._path)
+        log.debug('tree get: %s = %s', self._path, value)
+        return value
+
+    @value.setter
+    def value(self, value):
+        """
+        set value of this node in Augeas tree
+        """
+        log.debug('tree set: %s = %s', self._path, value)
+        self._aug.set(self._path, value)
+
+    @property
+    def span(self):
+        if self._span is None:
+            self._span = "char position %s" % self._aug.span(self._path)[5]
+        return self._span
+
+    @property
+    def char(self):
+        return self._aug.span(self._path)[5]
+
+    def __len__(self):
+        """
+        number of items matching this path
+
+        It is always 1 after __init__() but it may change
+        as Augeas tree changes.
+        """
+        return len(self._aug.match(self._path))
+
+    def __getitem__(self, key):
+        if isinstance(key, int):
+            # int is a shortcut to write [int]
+            target_path = '%s[%s]' % (self._path, key)
+        else:
+            target_path = self._path + key
+        log.debug('tree getitem: target_path %s', target_path)
+        paths = self._aug.match(target_path)
+        if len(paths) != 1:
+            raise KeyError('path %s did not match exactly once' % target_path)
+        return AugeasNode(self._aug, target_path)
+
+    def __delitem__(self, key):
+        log.debug('tree delitem: %s + %s', self._path, key)
+        target_path = self._path + key
+        log.debug('tree delitem: target_path %s', target_path)
+        self._aug.remove(target_path)
+
+    def __setitem__(self, key, value):
+        assert isinstance(value, AugeasNode)
+        target_path = self.path + key
+        self._aug.copy(value.path, target_path)
+
+    def __iter__(self):
+        self_path_len = len(self._path)
+        assert self_path_len > 0
+
+        log.debug('tree iter: %s', self._path)
+        for new_path in self._aug.match(self._path):
+            if len(new_path) == self_path_len:
+                yield ''
+            else:
+                yield new_path[self_path_len - 1:]
+
+    def match(self, subpath):
+        """Yield AugeasNodes matching given sub-expression."""
+        assert subpath.startswith("/")
+        match_path = "%s%s" % (self._path, subpath)
+        log.debug('tree match %s: %s', match_path, self._path)
+        for matched_path in self._aug.match(match_path):
+            yield AugeasNode(self._aug, matched_path)
+
+    def __repr__(self):
+        return 'AugeasNode(%s)' % self._path
diff --git a/tests/integration/deckard/pydnstest/deckard.aug b/tests/integration/deckard/pydnstest/deckard.aug
new file mode 100644
index 0000000..9e2d167
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/deckard.aug
@@ -0,0 +1,94 @@
+module Deckard =
+  autoload xfm
+
+let del_str = Util.del_str
+
+let space = del /[ \t]+/ " "
+let tab = del /[ \t]+/ "\t"
+let ws = del /[\t ]*/ ""
+let word = /[^\t\n\/; ]+/
+
+let comment = del /[;]/ ";" . [label "comment" . store /[^\n]+/]
+
+let eol = del /([ \t]*([;][^\n]*)?\n)+/ "\n" . Util.indent
+let comment_or_eol =  ws . comment? . del_str "\n" . del /([ \t]*([;][^\n]*)?\n)*/ "" . Util.indent
+
+
+(*let comment_or_eol = [ label "#comment" . counter "comment" . (ws . [del /[;#]/ ";" . label "" . store /[^\n]*/ ]? . del_str "\n")]+ . Util.indent
+*)
+
+
+let domain_re = (/[^.\t\n\/; ]+(\.[^.\t\n\/; ]+)*\.?/ | ".") - "SECTION" (*quick n dirty, sorry to whoever will ever own SECTION TLD*)
+let class_re = /CLASS[0-9]+/ | "IN" | "CH" | "HS" | "NONE" | "ANY"
+let domain = [ label "domain" . store domain_re ]
+let ttl = [label "ttl" . store /[0-9]+/]
+let class = [label "class" . store class_re ]
+let type = [label "type" . store ((/[^0-9;\n \t][^\t\n\/; ]*/) - class_re) ]
+(* RFC 3597 section 5 rdata syntax is "\# 1 ab"*)
+let data_re = /((\\#[ \t])?[^ \t\n;][^\n;]*[^ \t\n;])|[^ \t\n;]/ (*Can not start nor end with whitespace but can have whitespace in the middle. Disjunction is there so we match strings of length one.*)
+let data = [label "data" . store data_re ]
+
+let ip_re = /[0-9a-f.:]+/
+let hex_re = /[0-9a-fA-F]+/
+
+
+let match_option =  "opcode" | "qtype" | "qcase" | "qname" | "subdomain" | "flags" | "rcode" | "question" | "answer" | "authority" | "additional" | "all" | "edns"
+let adjust_option = "copy_id" | "copy_query" | "raw_id" | "do_not_answer"
+let reply_option = "QR" | "TC" | "AA" | "AD" | "RD" | "RA" | "CD" | "DO" | "NOERROR" | "FORMERR" | "SERVFAIL" | "NXDOMAIN" | "NOTIMP" | "REFUSED" | "YXDOMAIN" | "YXRRSET" | "NXRRSET" | "NOTAUTH" | "NOTZONE" | "BADVERS" | "BADSIG" | "BADKEY" | "BADTIME" | "BADMODE" | "BADNAME" | "BADALG" | "BADTRUNC" | "BADCOOKIE"
+let step_option = "REPLY" | "QUERY" | "CHECK_ANSWER" | "CHECK_OUT_QUERY" | /TIME_PASSES[ \t]+ELAPSE/
+
+let mandatory = [del_str "MANDATORY" . label "mandatory" . value "true" . comment_or_eol]
+let tsig = [del_str "TSIG" . label "tsig" . space . [label "keyname" . store word] . space . [label "secret" . store word] . comment_or_eol]
+
+let match = (mandatory | tsig)* . [ label "match_present" . value "true" . del_str "MATCH" ] . [space . label "match" . store match_option ]+ . comment_or_eol
+let adjust =  (mandatory | tsig)* . del_str "ADJUST" . [space . label "adjust" . store adjust_option ]+ . comment_or_eol
+let reply =  (mandatory | tsig)* . del ("REPLY" | "FLAGS") "REPLY" .  [space . label "reply" . store reply_option ]+ . comment_or_eol
+
+
+let question = [label "record" . domain . tab . (class . tab)? . type . comment_or_eol ]
+let record = [label "record" . domain . tab . (ttl . tab)? . (class . tab)? . type . tab . data . comment_or_eol]
+
+let section_question = [ label "question" . del_str "SECTION QUESTION" .
+                       comment_or_eol . question? ]
+let section_answer = [ label "answer" . del_str "SECTION ANSWER" .
+                       comment_or_eol . record* ]
+let section_authority = [ label "authority" . del_str "SECTION AUTHORITY" .
+                          comment_or_eol . record* ]
+let section_additional = [ label "additional" . del_str "SECTION ADDITIONAL" .
+                           comment_or_eol . record* ]
+let sections = [label "section" . section_question? . section_answer? . section_authority? . section_additional?]
+let raw = [del_str "RAW" . comment_or_eol . label "raw" . store hex_re  ] . comment_or_eol
+
+(* This is quite dirty hack to match every combination of options given to entry since 'let dnsmsg = ((match | adjust | reply | mandatory | tsig)* . sections)' just is not possible *)
+
+let dnsmsg = (match . (adjust . reply? | reply . adjust?)? | adjust . (match . reply? | reply . match?)? | reply . (match . adjust? | adjust . match?)?)? . (mandatory | tsig)* . sections
+
+let entry = [label "entry" . del_str "ENTRY_BEGIN" . comment_or_eol . dnsmsg . raw? . del_str "ENTRY_END" . eol]
+
+let single_address = [ label "address" . space . store ip_re ]
+
+let addresses = [label "address" . counter "address" . [seq "address" . del_str "ADDRESS" . space . store ip_re . comment_or_eol]+]
+
+let range = [label "range" . del_str "RANGE_BEGIN" . space . [ label "from" . store /[0-9]+/] . space .
+            [ label "to" . store /[0-9]+/] . single_address? . comment_or_eol . addresses? . entry* . del_str "RANGE_END" . eol]
+
+let step = [label "step" . del_str "STEP" . space . store /[0-9]+/ . space . [label "type" . store step_option] . [space . label "timestamp" . store /[0-9]+/]? . comment_or_eol .
+           entry? ]
+
+let config_record = /[^\n]*/ - ("CONFIG_END" | /STEP.*/ | /SCENARIO.*/ | /RANGE.*/ | /ENTRY.*/)
+
+let config = [ label "config" . counter "config" . [seq "config" . store config_record . del_str "\n"]* . del_str "CONFIG_END" . comment_or_eol ]
+
+let guts = (step | range )*
+
+let scenario = [label "scenario" . del_str "SCENARIO_BEGIN" . space . store data_re . comment_or_eol . guts . del_str "SCENARIO_END" . eol]
+
+let lns = config? . scenario
+
+(* TODO: REPLAY step *)
+(* TODO: store all comments into the tree instead of ignoring them *)
+
+(*let filter = incl "/home/test/*.rpl"*)
+let filter = incl "/home/sbalazik/nic/deckard/git/sets/resolver/*.rpl"
+
+let xfm = transform lns filter
diff --git a/tests/integration/deckard/pydnstest/empty.rpl b/tests/integration/deckard/pydnstest/empty.rpl
new file mode 100644
index 0000000..295d5a5
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/empty.rpl
@@ -0,0 +1,20 @@
+stub-addr: 127.0.0.10
+CONFIG_END
+
+SCENARIO_BEGIN empty replies
+
+RANGE_BEGIN 0 100
+	ADDRESS 127.0.0.10
+ENTRY_BEGIN
+MATCH subdomain
+ADJUST copy_id copy_query
+SECTION QUESTION
+. IN A
+ENTRY_END
+RANGE_END
+
+STEP 1 QUERY
+ENTRY_BEGIN
+ENTRY_END
+
+SCENARIO_END
diff --git a/tests/integration/deckard/pydnstest/matchpart.py b/tests/integration/deckard/pydnstest/matchpart.py
new file mode 100644
index 0000000..4a9d8a0
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/matchpart.py
@@ -0,0 +1,238 @@
+"""matchpart is used to compare two DNS messages using a single criterion"""
+
+from typing import (  # noqa
+    Any, Hashable, Sequence, Tuple, Union)
+
+import dns.edns
+import dns.rcode
+import dns.set
+
+MismatchValue = Union[str, Sequence[Any]]
+
+
+class DataMismatch(Exception):
+    def __init__(self, exp_val, got_val):
+        super().__init__()
+        self.exp_val = exp_val
+        self.got_val = got_val
+
+    @staticmethod
+    def format_value(value: MismatchValue) -> str:
+        if isinstance(value, list):
+            return ' '.join([str(val) for val in value])
+        else:
+            return str(value)
+
+    def __str__(self) -> str:
+        return 'expected "{}" got "{}"'.format(
+            self.format_value(self.exp_val),
+            self.format_value(self.got_val))
+
+    def __eq__(self, other):
+        return (isinstance(other, DataMismatch)
+                and self.exp_val == other.exp_val
+                and self.got_val == other.got_val)
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    @property
+    def key(self) -> Tuple[Hashable, Hashable]:
+        def make_hashable(value):
+            if isinstance(value, (list, dns.set.Set)):
+                value = (make_hashable(item) for item in value)
+                value = tuple(value)
+            return value
+
+        return (make_hashable(self.exp_val), make_hashable(self.got_val))
+
+    def __hash__(self) -> int:
+        return hash(self.key)
+
+
+def compare_val(exp, got):
+    """Compare arbitraty objects, throw exception if different. """
+    if exp != got:
+        raise DataMismatch(exp, got)
+    return True
+
+
+def compare_rrs(expected, got):
+    """ Compare lists of RR sets, throw exception if different. """
+    for rr in expected:
+        if rr not in got:
+            raise DataMismatch(expected, got)
+    for rr in got:
+        if rr not in expected:
+            raise DataMismatch(expected, got)
+    if len(expected) != len(got):
+        raise DataMismatch(expected, got)
+    return True
+
+
+def compare_rrs_types(exp_val, got_val, skip_rrsigs):
+    """sets of RR types in both sections must match"""
+    def rr_ordering_key(rrset):
+        if rrset.covers:
+            return rrset.covers, 1  # RRSIGs go to the end of RRtype list
+        else:
+            return rrset.rdtype, 0
+
+    def key_to_text(rrtype, rrsig):
+        if not rrsig:
+            return dns.rdatatype.to_text(rrtype)
+        else:
+            return 'RRSIG(%s)' % dns.rdatatype.to_text(rrtype)
+
+    if skip_rrsigs:
+        exp_val = (rrset for rrset in exp_val
+                   if rrset.rdtype != dns.rdatatype.RRSIG)
+        got_val = (rrset for rrset in got_val
+                   if rrset.rdtype != dns.rdatatype.RRSIG)
+
+    exp_types = frozenset(rr_ordering_key(rrset) for rrset in exp_val)
+    got_types = frozenset(rr_ordering_key(rrset) for rrset in got_val)
+    if exp_types != got_types:
+        exp_types = tuple(key_to_text(*i) for i in sorted(exp_types))
+        got_types = tuple(key_to_text(*i) for i in sorted(got_types))
+        raise DataMismatch(exp_types, got_types)
+
+
+def check_question(question):
+    if len(question) > 2:
+        raise NotImplementedError("More than one record in QUESTION SECTION.")
+
+
+def match_opcode(exp, got):
+    return compare_val(exp.opcode(),
+                       got.opcode())
+
+
+def match_qtype(exp, got):
+    check_question(exp.question)
+    check_question(got.question)
+    if not exp.question and not got.question:
+        return True
+    if not exp.question:
+        raise DataMismatch("<empty question>", got.question[0].rdtype)
+    if not got.question:
+        raise DataMismatch(exp.question[0].rdtype, "<empty question>")
+    return compare_val(exp.question[0].rdtype,
+                       got.question[0].rdtype)
+
+
+def match_qname(exp, got):
+    check_question(exp.question)
+    check_question(got.question)
+    if not exp.question and not got.question:
+        return True
+    if not exp.question:
+        raise DataMismatch("<empty question>", got.question[0].name)
+    if not got.question:
+        raise DataMismatch(exp.question[0].name, "<empty question>")
+    return compare_val(exp.question[0].name,
+                       got.question[0].name)
+
+
+def match_qcase(exp, got):
+    check_question(exp.question)
+    check_question(got.question)
+    if not exp.question and not got.question:
+        return True
+    if not exp.question:
+        raise DataMismatch("<empty question>", got.question[0].name.labels)
+    if not got.question:
+        raise DataMismatch(exp.question[0].name.labels, "<empty question>")
+    return compare_val(exp.question[0].name.labels,
+                       got.question[0].name.labels)
+
+
+def match_subdomain(exp, got):
+    if not exp.question:
+        return True
+    if got.question:
+        qname = got.question[0].name
+    else:
+        qname = dns.name.root
+    if exp.question[0].name.is_superdomain(qname):
+        return True
+    raise DataMismatch(exp, got)
+
+
+def match_flags(exp, got):
+    return compare_val(dns.flags.to_text(exp.flags),
+                       dns.flags.to_text(got.flags))
+
+
+def match_rcode(exp, got):
+    return compare_val(dns.rcode.to_text(exp.rcode()),
+                       dns.rcode.to_text(got.rcode()))
+
+
+def match_answer(exp, got):
+    return compare_rrs(exp.answer,
+                       got.answer)
+
+
+def match_answertypes(exp, got):
+    return compare_rrs_types(exp.answer,
+                             got.answer, skip_rrsigs=True)
+
+
+def match_answerrrsigs(exp, got):
+    return compare_rrs_types(exp.answer,
+                             got.answer, skip_rrsigs=False)
+
+
+def match_authority(exp, got):
+    return compare_rrs(exp.authority,
+                       got.authority)
+
+
+def match_additional(exp, got):
+    return compare_rrs(exp.additional,
+                       got.additional)
+
+
+def match_edns(exp, got):
+    if got.edns != exp.edns:
+        raise DataMismatch(exp.edns,
+                           got.edns)
+    if got.payload != exp.payload:
+        raise DataMismatch(exp.payload,
+                           got.payload)
+
+
+def match_nsid(exp, got):
+    nsid_opt = None
+    for opt in exp.options:
+        if opt.otype == dns.edns.NSID:
+            nsid_opt = opt
+            break
+    # Find matching NSID
+    for opt in got.options:
+        if opt.otype == dns.edns.NSID:
+            if not nsid_opt:
+                raise DataMismatch(None, opt.data)
+            if opt == nsid_opt:
+                return True
+            else:
+                raise DataMismatch(nsid_opt.data, opt.data)
+    if nsid_opt:
+        raise DataMismatch(nsid_opt.data, None)
+    return True
+
+
+MATCH = {"opcode": match_opcode, "qtype": match_qtype, "qname": match_qname, "qcase": match_qcase,
+         "subdomain": match_subdomain, "flags": match_flags, "rcode": match_rcode,
+         "answer": match_answer, "answertypes": match_answertypes,
+         "answerrrsigs": match_answerrrsigs, "authority": match_authority,
+         "additional": match_additional, "edns": match_edns,
+         "nsid": match_nsid}
+
+
+def match_part(exp, got, code):
+    try:
+        return MATCH[code](exp, got)
+    except KeyError as ex:
+        raise NotImplementedError('unknown match request "%s"' % code) from ex
diff --git a/tests/integration/deckard/pydnstest/mock_client.py b/tests/integration/deckard/pydnstest/mock_client.py
new file mode 100644
index 0000000..6089a21
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/mock_client.py
@@ -0,0 +1,136 @@
+"""Module takes care of sending and recieving DNS messages as a mock client"""
+
+import errno
+import socket
+import struct
+import time
+from typing import Optional, Tuple, Union
+
+import dns.message
+import dns.inet
+
+
+SOCKET_OPERATION_TIMEOUT = 5
+RECEIVE_MESSAGE_SIZE = 2**16-1
+THROTTLE_BY = 0.1
+
+
+def handle_socket_timeout(sock: socket.socket, deadline: float):
+    # deadline is always time.monotonic
+    remaining = deadline - time.monotonic()
+    if remaining <= 0:
+        raise RuntimeError("Server took too long to respond")
+    sock.settimeout(remaining)
+
+
+def recv_n_bytes_from_tcp(stream: socket.socket, n: int, deadline: float) -> bytes:
+    # deadline is always time.monotonic
+    data = b""
+    while n != 0:
+        handle_socket_timeout(stream, deadline)
+        chunk = stream.recv(n)
+        # Empty bytes from socket.recv mean that socket is closed
+        if not chunk:
+            raise OSError()
+        n -= len(chunk)
+        data += chunk
+    return data
+
+
+def recvfrom_blob(sock: socket.socket,
+                  timeout: int = SOCKET_OPERATION_TIMEOUT) -> Tuple[bytes, str]:
+    """
+    Receive DNS message from TCP/UDP socket.
+    """
+
+    # deadline is always time.monotonic
+    deadline = time.monotonic() + timeout
+
+    while True:
+        try:
+            if sock.type & socket.SOCK_DGRAM:
+                handle_socket_timeout(sock, deadline)
+                data, addr = sock.recvfrom(RECEIVE_MESSAGE_SIZE)
+            elif sock.type & socket.SOCK_STREAM:
+                # First 2 bytes of TCP packet are the size of the message
+                # See https://tools.ietf.org/html/rfc1035#section-4.2.2
+                data = recv_n_bytes_from_tcp(sock, 2, deadline)
+                msg_len = struct.unpack_from("!H", data)[0]
+                data = recv_n_bytes_from_tcp(sock, msg_len, deadline)
+                addr = sock.getpeername()[0]
+            else:
+                raise NotImplementedError("[recvfrom_blob]: unknown socket type '%i'" % sock.type)
+            return data, addr
+        except socket.timeout as ex:
+            raise RuntimeError("Server took too long to respond") from ex
+        except OSError as ex:
+            if ex.errno == errno.ENOBUFS:
+                time.sleep(0.1)
+            else:
+                raise
+
+
+def recvfrom_msg(sock: socket.socket,
+                 timeout: int = SOCKET_OPERATION_TIMEOUT) -> Tuple[dns.message.Message, str]:
+    data, addr = recvfrom_blob(sock, timeout=timeout)
+    msg = dns.message.from_wire(data, one_rr_per_rrset=True)
+    return msg, addr
+
+
+def sendto_msg(sock: socket.socket, message: bytes, addr: Optional[str] = None) -> None:
+    """ Send DNS/UDP/TCP message. """
+    try:
+        if sock.type & socket.SOCK_DGRAM:
+            if addr is None:
+                sock.send(message)
+            else:
+                sock.sendto(message, addr)
+        elif sock.type & socket.SOCK_STREAM:
+            data = struct.pack("!H", len(message)) + message
+            sock.sendall(data)
+        else:
+            raise NotImplementedError("[sendto_msg]: unknown socket type '%i'" % sock.type)
+    except OSError as ex:
+        # Reference: http://lkml.iu.edu/hypermail/linux/kernel/0002.3/0709.html
+        if ex.errno != errno.ECONNREFUSED:
+            raise
+
+
+def setup_socket(address: str,
+                 port: int,
+                 tcp: bool = False,
+                 src_address: str = None) -> socket.socket:
+    family = dns.inet.af_for_address(address)
+    sock = socket.socket(family, socket.SOCK_STREAM if tcp else socket.SOCK_DGRAM)
+    if tcp:
+        sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
+    if src_address is not None:
+        sock.bind((src_address, 0))  # random source port
+    sock.settimeout(SOCKET_OPERATION_TIMEOUT)
+    sock.connect((address, port))
+    return sock
+
+
+def send_query(sock: socket.socket, query: Union[dns.message.Message, bytes]) -> None:
+    message = query if isinstance(query, bytes) else query.to_wire()
+    while True:
+        try:
+            sendto_msg(sock, message)
+            break
+        except OSError as ex:
+            # ENOBUFS, throttle sending
+            if ex.errno == errno.ENOBUFS:
+                time.sleep(0.1)
+            else:
+                raise
+
+
+def get_answer(sock: socket.socket, timeout: int = SOCKET_OPERATION_TIMEOUT) -> bytes:
+    """ Compatibility function """
+    answer, _ = recvfrom_blob(sock, timeout=timeout)
+    return answer
+
+
+def get_dns_message(sock: socket.socket,
+                    timeout: int = SOCKET_OPERATION_TIMEOUT) -> dns.message.Message:
+    return dns.message.from_wire(get_answer(sock, timeout=timeout))
diff --git a/tests/integration/deckard/pydnstest/scenario.py b/tests/integration/deckard/pydnstest/scenario.py
new file mode 100644
index 0000000..9ef318c
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/scenario.py
@@ -0,0 +1,888 @@
+from abc import ABC
+import binascii
+import calendar
+from datetime import datetime
+import logging
+import os  # requires posix
+import random
+import socket
+import struct
+import time
+from typing import Optional
+
+import dns.dnssec
+import dns.message
+import dns.name
+import dns.rcode
+import dns.rrset
+import dns.tsigkeyring
+
+import pydnstest.augwrap
+import pydnstest.matchpart
+import pydnstest.mock_client
+
+
+def str2bool(v):
+    """ Return conversion of JSON-ish string value to boolean. """
+    return v.lower() in ('yes', 'true', 'on', '1')
+
+
+# Global statistics
+g_rtt = 0.0
+g_nqueries = 0
+
+
+class DNSBlob(ABC):
+    def to_wire(self) -> bytes:
+        raise NotImplementedError
+
+    def __str__(self) -> str:
+        return '<DNSBlob>'
+
+
+class DNSMessage(DNSBlob):
+    def __init__(self, message: dns.message.Message) -> None:
+        assert message is not None
+        self.message = message
+
+    def to_wire(self) -> bytes:
+        return self.message.to_wire(max_size=65535)
+
+    def __str__(self) -> str:
+        return str(self.message)
+
+
+class DNSReply(DNSMessage):
+    def __init__(
+                self,
+                message: dns.message.Message,
+                query: Optional[dns.message.Message] = None,
+                copy_id: bool = False,
+                copy_query: bool = False
+            ) -> None:
+        super().__init__(message)
+        if copy_id or copy_query:
+            if query is None:
+                raise ValueError("query must be provided to adjust copy_id/copy_query")
+            self.adjust_reply(query, copy_id, copy_query)
+
+    def adjust_reply(
+                self,
+                query: dns.message.Message,
+                copy_id: bool = True,
+                copy_query: bool = True
+            ) -> None:
+        answer = dns.message.from_wire(self.message.to_wire(),
+                                       xfr=self.message.xfr,
+                                       one_rr_per_rrset=True)
+        answer.use_edns(query.edns, query.ednsflags, options=self.message.options)
+        if copy_id:
+            answer.id = query.id
+            # Copy letter-case if the template has QD
+            if answer.question:
+                answer.question[0].name = query.question[0].name
+        if copy_query:
+            answer.question = query.question
+        # Re-set, as the EDNS might have reset the ext-rcode
+        answer.set_rcode(self.message.rcode())
+
+        # sanity check: adjusted answer should be almost the same
+        assert len(answer.answer) == len(self.message.answer)
+        assert len(answer.authority) == len(self.message.authority)
+        assert len(answer.additional) == len(self.message.additional)
+        self.message = answer
+
+
+class DNSReplyRaw(DNSBlob):
+    def __init__(
+                self,
+                wire: bytes,
+                query: Optional[dns.message.Message] = None,
+                copy_id: bool = False
+            ) -> None:
+        assert wire is not None
+        self.wire = wire
+        if copy_id:
+            if query is None:
+                raise ValueError("query must be provided to adjust copy_id")
+            self.adjust_reply(query, copy_id)
+
+    def adjust_reply(
+                self,
+                query: dns.message.Message,
+                raw_id: bool = True
+            ) -> None:
+        if raw_id:
+            if len(self.wire) < 2:
+                raise ValueError(
+                    'wire data must contain at least 2 bytes to adjust query id')
+            raw_answer = bytearray(self.wire)
+            struct.pack_into('!H', raw_answer, 0, query.id)
+            self.wire = bytes(raw_answer)
+
+    def to_wire(self) -> bytes:
+        return self.wire
+
+    def __str__(self) -> str:
+        return '<DNSReplyRaw>'
+
+
+class DNSReplyServfail(DNSMessage):
+    def __init__(self, query: dns.message.Message) -> None:
+        message = dns.message.make_response(query)
+        message.set_rcode(dns.rcode.SERVFAIL)
+        super().__init__(message)
+
+
+class Entry:
+    """
+    Data entry represents scripted message and extra metadata,
+    notably match criteria and reply adjustments.
+    """
+
+    # Globals
+    default_ttl = 3600
+    default_cls = 'IN'
+    default_rc = 'NOERROR'
+
+    def __init__(self, node):
+        """ Initialize data entry. """
+        self.node = node
+        self.origin = '.'
+        self.message = dns.message.Message()
+        self.message.use_edns(edns=0, payload=4096)
+        self.fired = 0
+
+        # RAW
+        self.raw_data = self.process_raw()
+
+        # MATCH
+        self.match_fields = self.process_match()
+
+        # FLAGS (old alias REPLY)
+        self.process_reply_line()
+
+        # ADJUST
+        self.adjust_fields = {m.value for m in node.match("/adjust")}
+
+        # MANDATORY
+        try:
+            self.mandatory = list(node.match("/mandatory"))[0]
+        except (KeyError, IndexError):
+            self.mandatory = None
+
+        # TSIG
+        self.process_tsig()
+
+        # SECTIONS & RECORDS
+        self.sections = self.process_sections()
+
+    def process_raw(self):
+        try:
+            return binascii.unhexlify(self.node["/raw"].value)
+        except KeyError:
+            return None
+
+    def process_match(self):
+        try:
+            self.node["/match_present"]
+        except KeyError:
+            return None
+
+        fields = set(m.value for m in self.node.match("/match"))
+
+        if 'all' in fields:
+            fields.remove("all")
+            fields |= set(["opcode", "qtype", "qname", "flags",
+                           "rcode", "answer", "authority", "additional"])
+
+        if 'question' in fields:
+            fields.remove("question")
+            fields |= set(["qtype", "qname"])
+
+        return fields
+
+    def process_reply_line(self):
+        """Extracts flags, rcode and opcode from given node and adjust dns message accordingly"""
+        fields = [f.value for f in self.node.match("/reply")]
+        if 'DO' in fields:
+            self.message.want_dnssec(True)
+        opcode = self.get_opcode(fields)
+        rcode = self.get_rcode(fields)
+        self.message.flags = self.get_flags(fields)
+        if rcode is not None:
+            self.message.set_rcode(rcode)
+        if opcode is not None:
+            self.message.set_opcode(opcode)
+
+    def process_tsig(self):
+        try:
+            tsig = list(self.node.match("/tsig"))[0]
+            tsig_keyname = tsig["/keyname"].value
+            tsig_secret = tsig["/secret"].value
+            keyring = dns.tsigkeyring.from_text({tsig_keyname: tsig_secret})
+            self.message.use_tsig(keyring=keyring, keyname=tsig_keyname)
+        except (KeyError, IndexError):
+            pass
+
+    def process_sections(self):
+        sections = set()
+        for section in self.node.match("/section/*"):
+            section_name = os.path.basename(section.path)
+            sections.add(section_name)
+            for record in section.match("/record"):
+                owner = record['/domain'].value
+                if not owner.endswith("."):
+                    owner += self.origin
+                try:
+                    ttl = dns.ttl.from_text(record['/ttl'].value)
+                except KeyError:
+                    ttl = self.default_ttl
+                try:
+                    rdclass = dns.rdataclass.from_text(record['/class'].value)
+                except KeyError:
+                    rdclass = dns.rdataclass.from_text(self.default_cls)
+                rdtype = dns.rdatatype.from_text(record['/type'].value)
+                rr = dns.rrset.from_text(owner, ttl, rdclass, rdtype)
+                if section_name != "question":
+                    rd = record['/data'].value.split()
+                    if rd:
+                        if rdtype == dns.rdatatype.DS:
+                            rd[1] = '{}'.format(dns.dnssec.algorithm_from_text(rd[1]))
+                        rd = dns.rdata.from_text(rr.rdclass, rr.rdtype, ' '.join(
+                            rd), origin=dns.name.from_text(self.origin), relativize=False)
+                    rr.add(rd)
+                if section_name == 'question':
+                    if rr.rdtype == dns.rdatatype.AXFR:
+                        self.message.xfr = True
+                    self.message.question.append(rr)
+                elif section_name == 'answer':
+                    self.message.answer.append(rr)
+                elif section_name == 'authority':
+                    self.message.authority.append(rr)
+                elif section_name == 'additional':
+                    self.message.additional.append(rr)
+        return sections
+
+    def __str__(self):
+        txt = 'ENTRY_BEGIN\n'
+        if self.raw_data is None:
+            txt += 'MATCH {0}\n'.format(' '.join(self.match_fields))
+        txt += 'ADJUST {0}\n'.format(' '.join(self.adjust_fields))
+        txt += 'REPLY {rcode} {flags}\n'.format(
+            rcode=dns.rcode.to_text(self.message.rcode()),
+            flags=' '.join([dns.flags.to_text(self.message.flags),
+                            dns.flags.edns_to_text(self.message.ednsflags)])
+        )
+        for sect_name in ['question', 'answer', 'authority', 'additional']:
+            sect = getattr(self.message, sect_name)
+            if not sect:
+                continue
+            txt += 'SECTION {n}\n'.format(n=sect_name.upper())
+            for rr in sect:
+                txt += str(rr)
+                txt += '\n'
+        if self.raw_data is not None:
+            txt += 'RAW\n'
+            if self.raw_data:
+                txt += binascii.hexlify(self.raw_data)
+            else:
+                txt += 'NULL'
+            txt += '\n'
+        txt += 'ENTRY_END\n'
+        return txt
+
+    @classmethod
+    def get_flags(cls, fields):
+        """From `fields` extracts and returns flags"""
+        flags = []
+        for code in fields:
+            try:
+                dns.flags.from_text(code)  # throws KeyError on failure
+                flags.append(code)
+            except KeyError:
+                pass
+        return dns.flags.from_text(' '.join(flags))
+
+    @classmethod
+    def get_rcode(cls, fields):
+        """
+        From `fields` extracts and returns rcode.
+        Throws `ValueError` if there are more then one rcodes
+        """
+        rcodes = []
+        for code in fields:
+            try:
+                rcodes.append(dns.rcode.from_text(code))
+            except dns.rcode.UnknownRcode:
+                pass
+        if len(rcodes) > 1:
+            raise ValueError("Parse failed, too many rcode values.", rcodes)
+        if not rcodes:
+            return None
+        return rcodes[0]
+
+    @classmethod
+    def get_opcode(cls, fields):
+        """
+        From `fields` extracts and returns opcode.
+        Throws `ValueError` if there are more then one opcodes
+        """
+        opcodes = []
+        for code in fields:
+            try:
+                opcodes.append(dns.opcode.from_text(code))
+            except dns.opcode.UnknownOpcode:
+                pass
+        if len(opcodes) > 1:
+            raise ValueError("Parse failed, too many opcode values.")
+        if not opcodes:
+            return None
+        return opcodes[0]
+
+    def match(self, msg):
+        """ Compare scripted reply to given message based on match criteria. """
+        for code in self.match_fields:
+            try:
+                pydnstest.matchpart.match_part(self.message, msg, code)
+            except pydnstest.matchpart.DataMismatch as ex:
+                errstr = '%s in the response:\n%s' % (str(ex), msg.to_text())
+                # TODO: cisla radku
+                raise ValueError("%s, \"%s\": %s" % (self.node.span, code, errstr)) from None
+
+    def cmp_raw(self, raw_value):
+        assert self.raw_data is not None
+        expected = None
+        if self.raw_data is not None:
+            expected = binascii.hexlify(self.raw_data)
+        got = None
+        if raw_value is not None:
+            got = binascii.hexlify(raw_value)
+        if expected != got:
+            raise ValueError("raw message comparsion failed: expected %s got %s" % (expected, got))
+
+    def reply(self, query) -> Optional[DNSBlob]:
+        if 'do_not_answer' in self.adjust_fields:
+            return None
+        if self.raw_data is not None:
+            raw_id = 'raw_id' in self.adjust_fields
+            assert self.raw_data is not None
+            return DNSReplyRaw(self.raw_data, query, raw_id)
+        copy_id = 'copy_id' in self.adjust_fields
+        copy_query = 'copy_query' in self.adjust_fields
+        return DNSReply(self.message, query, copy_id, copy_query)
+
+    def set_edns(self, fields):
+        """ Set EDNS version and bufsize. """
+        version = 0
+        bufsize = 4096
+        if fields and fields[0].isdigit():
+            version = int(fields.pop(0))
+        if fields and fields[0].isdigit():
+            bufsize = int(fields.pop(0))
+        if bufsize == 0:
+            self.message.use_edns(False)
+            return
+        opts = []
+        for v in fields:
+            k, v = tuple(v.split('=')) if '=' in v else (v, True)
+            if k.lower() == 'nsid':
+                opts.append(dns.edns.GenericOption(dns.edns.NSID, '' if v is True else v))
+            if k.lower() == 'subnet':
+                net = v.split('/')
+                subnet_addr = net[0]
+                family = socket.AF_INET6 if ':' in subnet_addr else socket.AF_INET
+                addr = socket.inet_pton(family, subnet_addr)
+                prefix = len(addr) * 8
+                if len(net) > 1:
+                    prefix = int(net[1])
+                addr = addr[0: (prefix + 7) / 8]
+                if prefix % 8 != 0:  # Mask the last byte
+                    addr = addr[:-1] + chr(ord(addr[-1]) & 0xFF << (8 - prefix % 8))
+                opts.append(dns.edns.GenericOption(8, struct.pack(
+                    "!HBB", 1 if family == socket.AF_INET else 2, prefix, 0) + addr))
+        self.message.use_edns(edns=version, payload=bufsize, options=opts)
+
+
+class Range:
+    """
+    Range represents a set of scripted queries valid for given step range.
+    """
+    log = logging.getLogger('pydnstest.scenario.Range')
+
+    def __init__(self, node):
+        """ Initialize reply range. """
+        self.node = node
+        self.a = int(node['/from'].value)
+        self.b = int(node['/to'].value)
+        assert self.a <= self.b
+
+        address = node["/address"].value
+        self.addresses = {address} if address is not None else set()
+        self.addresses |= {a.value for a in node.match("/address/*")}
+        self.stored = [Entry(n) for n in node.match("/entry")]
+        self.args = {}
+        self.received = 0
+        self.sent = 0
+
+    def __del__(self):
+        self.log.info('[ RANGE %d-%d ] %s received: %d sent: %d',
+                      self.a, self.b, self.addresses, self.received, self.sent)
+
+    def __str__(self):
+        txt = '\nRANGE_BEGIN {a} {b}\n'.format(a=self.a, b=self.b)
+        for addr in self.addresses:
+            txt += '        ADDRESS {0}\n'.format(addr)
+
+        for entry in self.stored:
+            txt += '\n'
+            txt += str(entry)
+        txt += 'RANGE_END\n\n'
+        return txt
+
+    def eligible(self, ident, address):
+        """ Return true if this range is eligible for fetching reply. """
+        if self.a <= ident <= self.b:
+            return (None is address
+                    or set() == self.addresses
+                    or address in self.addresses)
+        return False
+
+    def reply(self, query: dns.message.Message) -> Optional[DNSBlob]:
+        """Get answer for given query (adjusted if needed)."""
+        self.received += 1
+        for candidate in self.stored:
+            try:
+                candidate.match(query)
+                resp = candidate.reply(query)
+                # Probabilistic loss
+                if 'LOSS' in self.args:
+                    if random.random() < float(self.args['LOSS']):
+                        return DNSReplyServfail(query)
+                self.sent += 1
+                candidate.fired += 1
+                return resp
+            except ValueError:
+                pass
+        return DNSReplyServfail(query)
+
+
+class StepLogger(logging.LoggerAdapter):  # pylint: disable=too-few-public-methods
+    """
+    Prepent Step identification before each log message.
+    """
+    def process(self, msg, kwargs):
+        return '[STEP %s %s] %s' % (self.extra['id'], self.extra['type'], msg), kwargs
+
+
+class Step:
+    """
+    Step represents one scripted action in a given moment,
+    each step has an order identifier, type and optionally data entry.
+    """
+    require_data = ['QUERY', 'CHECK_ANSWER', 'REPLY']
+
+    def __init__(self, node):
+        """ Initialize single scenario step. """
+        self.node = node
+        self.id = int(node.value)
+        self.type = node["/type"].value
+        self.log = StepLogger(logging.getLogger('pydnstest.scenario.Step'),
+                              {'id': self.id, 'type': self.type})
+        try:
+            self.delay = int(node["/timestamp"].value)
+        except KeyError:
+            pass
+        self.data = [Entry(n) for n in node.match("/entry")]
+        self.queries = []
+        self.has_data = self.type in Step.require_data
+        self.answer = None
+        self.raw_answer = None
+        self.repeat_if_fail = 0
+        self.pause_if_fail = 0
+        self.next_if_fail = -1
+
+    def __str__(self):
+        txt = '\nSTEP {i} {t}'.format(i=self.id, t=self.type)
+        if self.repeat_if_fail:
+            txt += ' REPEAT {v}'.format(v=self.repeat_if_fail)
+        elif self.pause_if_fail:
+            txt += ' PAUSE {v}'.format(v=self.pause_if_fail)
+        elif self.next_if_fail != -1:
+            txt += ' NEXT {v}'.format(v=self.next_if_fail)
+        # if self.args:
+        #     txt += ' '
+        #     txt += ' '.join(self.args)
+        txt += '\n'
+
+        for data in self.data:
+            # from IPython.core.debugger import Tracer
+            # Tracer()()
+            txt += str(data)
+        return txt
+
+    def play(self, ctx):
+        """ Play one step from a scenario. """
+        if self.type == 'QUERY':
+            self.log.info('')
+            self.log.debug(self.data[0].message.to_text())
+            # Parse QUERY-specific parameters
+            choice, tcp, src_address = None, False, ctx.deckard_address
+            return self.__query(ctx, tcp=tcp, choice=choice, src_address=src_address)
+        elif self.type == 'CHECK_OUT_QUERY':  # ignore
+            self.log.info('')
+            return None
+        elif self.type == 'CHECK_ANSWER' or self.type == 'ANSWER':
+            self.log.info('')
+            return self.__check_answer(ctx)
+        elif self.type == 'TIME_PASSES ELAPSE':
+            self.log.info('')
+            return self.__time_passes()
+        elif self.type == 'REPLY' or self.type == 'MOCK':
+            self.log.info('')
+            return None
+        else:
+            raise NotImplementedError('step %03d type %s unsupported' % (self.id, self.type))
+
+    def __check_answer(self, ctx):
+        """ Compare answer from previously resolved query. """
+        if not self.data:
+            raise ValueError("response definition required")
+        expected = self.data[0]
+        if expected.raw_data is not None:
+            self.log.debug("raw answer: %s", ctx.last_raw_answer.to_text())
+            expected.cmp_raw(ctx.last_raw_answer)
+        else:
+            if ctx.last_answer is None:
+                raise ValueError("no answer from preceding query")
+            self.log.debug("answer: %s", ctx.last_answer.to_text())
+            expected.match(ctx.last_answer)
+
+    def __query(self, ctx, tcp=False, choice=None, src_address=None):
+        """
+        Send query and wait for an answer (if the query is not RAW).
+
+        The received answer is stored in self.answer and ctx.last_answer.
+        """
+        if not self.data:
+            raise ValueError("query definition required")
+        if self.data[0].raw_data is not None:
+            data_to_wire = self.data[0].raw_data
+        else:
+            # Don't use a message copy as the EDNS data portion is not copied.
+            data_to_wire = self.data[0].message.to_wire()
+        if choice is None or not choice:
+            choice = list(ctx.client.keys())[0]
+        if choice not in ctx.client:
+            raise ValueError('step %03d invalid QUERY target: %s' % (self.id, choice))
+
+        tstart = datetime.now()
+
+        # Send query and wait for answer
+        answer = None
+        sock = pydnstest.mock_client.setup_socket(ctx.client[choice][0],
+                                                  ctx.client[choice][1],
+                                                  tcp,
+                                                  src_address=src_address)
+        with sock:
+            pydnstest.mock_client.send_query(sock, data_to_wire)
+            if self.data[0].raw_data is None:
+                answer = pydnstest.mock_client.get_answer(sock)
+
+        # Track RTT
+        rtt = (datetime.now() - tstart).total_seconds() * 1000
+        global g_rtt, g_nqueries
+        g_nqueries += 1
+        g_rtt += rtt
+
+        # Remember last answer for checking later
+        self.raw_answer = answer
+        ctx.last_raw_answer = answer
+        if self.raw_answer is not None:
+            self.answer = dns.message.from_wire(self.raw_answer, one_rr_per_rrset=True)
+        else:
+            self.answer = None
+        ctx.last_answer = self.answer
+
+    def __time_passes(self):
+        """ Modify system time. """
+        file_old = os.environ["FAKETIME_TIMESTAMP_FILE"]
+        file_next = os.environ["FAKETIME_TIMESTAMP_FILE"] + ".next"
+        with open(file_old, 'r') as time_file:
+            line = time_file.readline().strip()
+        t = time.mktime(datetime.strptime(line, '@%Y-%m-%d %H:%M:%S').timetuple())
+        t += self.delay
+        with open(file_next, 'w') as time_file:
+            time_file.write(datetime.fromtimestamp(t).strftime('@%Y-%m-%d %H:%M:%S') + "\n")
+            time_file.flush()
+        os.replace(file_next, file_old)
+
+
+class Scenario:
+    log = logging.getLogger('pydnstest.scenatio.Scenario')
+
+    def __init__(self, node, filename, deckard_address=None):
+        """ Initialize scenario with description. """
+        self.node = node
+        self.info = node.value
+        self.file = filename
+        self.ranges = [Range(n) for n in node.match("/range")]
+        self.current_range = None
+        self.steps = [Step(n) for n in node.match("/step")]
+        self.current_step = None
+        self.client = {}
+        self.deckard_address = deckard_address
+
+    def __str__(self):
+        txt = 'SCENARIO_BEGIN'
+        if self.info:
+            txt += ' {0}'.format(self.info)
+        txt += '\n'
+        for range_ in self.ranges:
+            txt += str(range_)
+        for step in self.steps:
+            txt += str(step)
+        txt += "\nSCENARIO_END"
+        return txt
+
+    def reply(self, query: dns.message.Message, address=None) -> Optional[DNSBlob]:
+        """Generate answer packet for given query."""
+        current_step_id = self.current_step.id
+        # Unknown address, select any match
+        # TODO: workaround until the server supports stub zones
+        all_addresses = set()  # type: ignore
+        for rng in self.ranges:
+            all_addresses.update(rng.addresses)
+        if address not in all_addresses:
+            address = None
+        # Find current valid query response range
+        for rng in self.ranges:
+            if rng.eligible(current_step_id, address):
+                self.current_range = rng
+                return rng.reply(query)
+        # Find any prescripted one-shot replies
+        for step in self.steps:
+            if step.id < current_step_id or step.type != 'REPLY':
+                continue
+            try:
+                candidate = step.data[0]
+                candidate.match(query)
+                step.data.remove(candidate)
+                return candidate.reply(query)
+            except (IndexError, ValueError):
+                pass
+        return DNSReplyServfail(query)
+
+    def play(self, paddr):
+        """ Play given scenario. """
+        # Store test subject => address mapping
+        self.client = paddr
+
+        step = None
+        i = 0
+        while i < len(self.steps):
+            step = self.steps[i]
+            self.current_step = step
+            try:
+                step.play(self)
+            except ValueError as ex:
+                if step.repeat_if_fail > 0:
+                    self.log.info("[play] step %d: exception - '%s', retrying step %d (%d left)",
+                                  step.id, ex, step.next_if_fail, step.repeat_if_fail)
+                    step.repeat_if_fail -= 1
+                    if step.pause_if_fail > 0:
+                        time.sleep(step.pause_if_fail)
+                    if step.next_if_fail != -1:
+                        next_steps = [j for j in range(len(self.steps)) if self.steps[
+                            j].id == step.next_if_fail]
+                        if not next_steps:
+                            raise ValueError('step %d: wrong NEXT value "%d"' %
+                                             (step.id, step.next_if_fail)) from ex
+                        next_step = next_steps[0]
+                        if next_step < len(self.steps):
+                            i = next_step
+                        else:
+                            raise ValueError('step %d: Can''t branch to NEXT value "%d"' %
+                                             (step.id, step.next_if_fail)) from ex
+                    continue
+                ex_details = ex if self.log.isEnabledFor(logging.DEBUG) else None
+                raise ValueError('%s step %d %s' % (self.file, step.id, str(ex))) from ex_details
+            i += 1
+
+        for r in self.ranges:
+            for e in r.stored:
+                if e.mandatory and e.fired == 0:
+                    # TODO: cisla radku
+                    raise ValueError('Mandatory section at %s not fired' % e.mandatory.span)
+
+
+def get_next(file_in, skip_empty=True):
+    """ Return next token from the input stream. """
+    while True:
+        line = file_in.readline()
+        if not line:
+            return False
+        quoted, escaped = False, False
+        for i, char in enumerate(line):
+            if char == '\\':
+                escaped = not escaped
+            if not escaped and char == '"':
+                quoted = not quoted
+            if char == ';' and not quoted:
+                line = line[0:i]
+                break
+            if char != '\\':
+                escaped = False
+        tokens = ' '.join(line.strip().split()).split()
+        if not tokens:
+            if skip_empty:
+                continue
+            return '', []
+        op = tokens.pop(0)
+        return op, tokens
+
+
+def parse_config(scn_cfg, qmin, installdir):  # FIXME: pylint: disable=too-many-statements
+    """
+    Transform scene config (key, value) pairs into dict filled with defaults.
+    Returns tuple:
+      context dict: {Jinja2 variable: value}
+      trust anchor dict: {domain: [TA lines for particular domain]}
+    """
+    # defaults
+    do_not_query_localhost = True
+    harden_glue = True
+    sockfamily = 0  # auto-select value for socket.getaddrinfo
+    trust_anchor_list = []
+    trust_anchor_files = {}
+    negative_ta_list = []
+    stub_addr = None
+    stub_name = "k.root-servers.net"
+    override_timestamp = None
+    forward_addr = None
+    do_ip6 = True
+    do_ip4 = True
+    features = {}
+    feature_list_delimiter = ';'
+    feature_pair_delimiter = '='
+
+    for k, v in scn_cfg:
+        # Enable selectively for some tests
+        if k == 'do-not-query-localhost':
+            do_not_query_localhost = str2bool(v)
+        elif k == 'domain-insecure':
+            negative_ta_list.append(v)
+        elif k == 'harden-glue':
+            harden_glue = str2bool(v)
+        elif k == 'query-minimization':
+            qmin = str2bool(v)
+        elif k == 'trust-anchor':
+            trust_anchor = v.strip('"\'')
+            trust_anchor_list.append(trust_anchor)
+            domain = dns.name.from_text(trust_anchor.split()[0]).canonicalize()
+            if domain not in trust_anchor_files:
+                trust_anchor_files[domain] = []
+            trust_anchor_files[domain].append(trust_anchor)
+        elif k == 'val-override-timestamp':
+            override_timestamp_str = v.strip('"\'')
+            override_timestamp = int(override_timestamp_str)
+        elif k == 'val-override-date':
+            override_date_str = v.strip('"\'')
+            ovr_yr = override_date_str[0:4]
+            ovr_mnt = override_date_str[4:6]
+            ovr_day = override_date_str[6:8]
+            ovr_hr = override_date_str[8:10]
+            ovr_min = override_date_str[10:12]
+            ovr_sec = override_date_str[12:]
+            override_date_str_arg = '{0} {1} {2} {3} {4} {5}'.format(
+                ovr_yr, ovr_mnt, ovr_day, ovr_hr, ovr_min, ovr_sec)
+            override_date = time.strptime(override_date_str_arg, "%Y %m %d %H %M %S")
+            override_timestamp = calendar.timegm(override_date)
+        elif k == 'stub-addr':
+            stub_addr = v.strip('"\'')
+        elif k == 'stub-name':
+            stub_name = v
+        elif k == 'features':
+            feature_list = v.split(feature_list_delimiter)
+            try:
+                for f_item in feature_list:
+                    if f_item.find(feature_pair_delimiter) != -1:
+                        f_key, f_value = [x.strip()
+                                          for x
+                                          in f_item.split(feature_pair_delimiter, 1)]
+                    else:
+                        f_key = f_item.strip()
+                        f_value = ""
+                    features[f_key] = f_value
+            except KeyError as ex:
+                raise KeyError("can't parse features (%s) in config section (%s)"
+                               % (v, str(ex))) from ex
+        elif k == 'feature-list':
+            try:
+                f_key, f_value = [x.strip() for x in v.split(feature_pair_delimiter, 1)]
+                if f_key not in features:
+                    features[f_key] = []
+                f_value = f_value.replace("{{INSTALL_DIR}}", installdir)
+                features[f_key].append(f_value)
+            except KeyError as ex:
+                raise KeyError("can't parse feature-list (%s) in config section (%s)"
+                               % (v, str(ex))) from ex
+        elif k == 'force-ipv6' and v.upper() == 'TRUE':
+            sockfamily = socket.AF_INET6
+        elif k == 'forward-addr':  # currently forwards everything
+            forward_addr = v.strip('"\'')
+        elif k == 'do-ip4':
+            do_ip4 = str2bool(v)
+        elif k == 'do-ip6':
+            do_ip6 = str2bool(v)
+        else:
+            raise NotImplementedError('unsupported CONFIG key "%s"' % k)
+
+    ctx = {
+        "DO_NOT_QUERY_LOCALHOST": str(do_not_query_localhost).lower(),
+        "NEGATIVE_TRUST_ANCHORS": negative_ta_list,
+        "FEATURES": features,
+        "HARDEN_GLUE": str(harden_glue).lower(),
+        "INSTALL_DIR": installdir,
+        "QMIN": str(qmin).lower(),
+        "TRUST_ANCHORS": trust_anchor_list,
+        "TRUST_ANCHOR_FILES": trust_anchor_files,
+        "FORWARD_ADDR": forward_addr,
+        "DO_IP6": str(do_ip6).lower(),
+        "DO_IP4": str(do_ip4).lower(),
+    }
+    if stub_addr:
+        ctx['ROOT_ADDR'] = stub_addr
+        ctx['ROOT_NAME'] = stub_name
+        # determine and verify socket family for specified root address
+        gai = socket.getaddrinfo(stub_addr, 53, sockfamily, 0,
+                                 socket.IPPROTO_UDP, socket.AI_NUMERICHOST)
+        assert len(gai) == 1
+        sockfamily = gai[0][0]
+    if not sockfamily:
+        sockfamily = socket.AF_INET  # default to IPv4
+    ctx['_SOCKET_FAMILY'] = sockfamily
+    if override_timestamp:
+        ctx['_OVERRIDE_TIMESTAMP'] = override_timestamp
+    return ctx
+
+
+def parse_file(path, deckard_address=None):
+    """ Parse scenario from a file. """
+
+    aug = pydnstest.augwrap.AugeasWrapper(
+        confpath=path, lens='Deckard', loadpath=os.path.dirname(__file__))
+    node = aug.tree
+    config = []
+    for line in [c.value for c in node.match("/config/*")]:
+        if line:
+            if not line.startswith(';'):
+                if '#' in line:
+                    line = line[0:line.index('#')]
+                # Break to key-value pairs
+                # e.g.: ['minimization', 'on']
+                kv = [x.strip() for x in line.split(':', 1)]
+                if len(kv) >= 2:
+                    config.append(kv)
+    scenario = Scenario(node["/scenario"], os.path.basename(node.path), deckard_address)
+    return scenario, config
diff --git a/tests/integration/deckard/pydnstest/tests/__init__.py b/tests/integration/deckard/pydnstest/tests/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/tests/__init__.py
diff --git a/tests/integration/deckard/pydnstest/tests/test_parse_config.py b/tests/integration/deckard/pydnstest/tests/test_parse_config.py
new file mode 100644
index 0000000..d8cdea1
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/tests/test_parse_config.py
@@ -0,0 +1,17 @@
+""" This is unittest file for parse methods in scenario.py """
+import os
+
+from pydnstest.scenario import parse_config
+
+
+def test_parse_config__trust_anchor():
+    """Checks if trust-anchors are separated into files according to domain."""
+    anchor1 = u'domain1.com.\t3600\tIN\tDS\t11901 7 1 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+    anchor2 = u'domain2.net.\t3600\tIN\tDS\t59835 7 1 cccccccccccccccccccccccccccccccccccccccc'
+    anchor3 = u'domain1.com.\t3600\tIN\tDS\t11902 7 1 1111111111111111111111111111111111111111'
+    anchors = [[u'trust-anchor', u'"{}"'.format(anchor1)],
+               [u'trust-anchor', u'"{}"'.format(anchor2)],
+               [u'trust-anchor', u'"{}"'.format(anchor3)]]
+    args = (anchors, True, os.getcwd())
+    ta_files = parse_config(*args)["TRUST_ANCHOR_FILES"]
+    assert sorted(ta_files.values()) == sorted([[anchor1, anchor3], [anchor2]])
diff --git a/tests/integration/deckard/pydnstest/tests/test_scenario.py b/tests/integration/deckard/pydnstest/tests/test_scenario.py
new file mode 100644
index 0000000..454cb5c
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/tests/test_scenario.py
@@ -0,0 +1,55 @@
+""" This is unittest file for scenario.py """
+
+import pytest
+
+from pydnstest.scenario import Entry
+
+RCODE_FLAGS = ['NOERROR', 'FORMERR', 'SERVFAIL', 'NXDOMAIN', 'NOTIMP', 'REFUSED', 'YXDOMAIN',
+               'YXRRSET', 'NXRRSET', 'NOTAUTH', 'NOTZONE', 'BADVERS']
+OPCODE_FLAGS = ['QUERY', 'IQUERY', 'STATUS', 'NOTIFY', 'UPDATE']
+FLAGS = ['QR', 'TC', 'AA', 'AD', 'RD', 'RA', 'CD']
+
+
+def test_entry__get_flags():
+    """Checks if all rcodes and opcodes are filtered out"""
+    expected_flags = Entry.get_flags(FLAGS)
+    for flag in RCODE_FLAGS + OPCODE_FLAGS:
+        rcode_flags = Entry.get_flags(FLAGS + [flag])
+        assert rcode_flags == expected_flags, \
+            'Entry._get_flags does not filter out "{flag}"'.format(flag=flag)
+
+
+def test_entry__get_rcode():
+    """
+    Checks if the error is raised for multiple rcodes
+    checks if None is returned for no rcode
+    checks if flags and opcode are filtered out
+    """
+    with pytest.raises(ValueError):
+        Entry.get_rcode(RCODE_FLAGS[:2])
+
+    assert Entry.get_rcode(FLAGS) is None
+    assert Entry.get_rcode([]) is None
+
+    for rcode in RCODE_FLAGS:
+        given_rcode = Entry.get_rcode(FLAGS + OPCODE_FLAGS + [rcode])
+        assert given_rcode is not None, 'Entry.get_rcode does not recognize {rcode}'.format(
+            rcode=rcode)
+
+
+def test_entry__get_opcode():
+    """
+    Checks if the error is raised for multiple opcodes
+    checks if None is returned for no opcode
+    checks if flags and opcode are filtered out
+    """
+    with pytest.raises(ValueError):
+        Entry.get_opcode(OPCODE_FLAGS[:2])
+
+    assert Entry.get_opcode(FLAGS) is None
+    assert Entry.get_opcode([]) is None
+
+    for opcode in OPCODE_FLAGS:
+        given_rcode = Entry.get_opcode(FLAGS + RCODE_FLAGS + [opcode])
+        assert given_rcode is not None, 'Entry.get_opcode does not recognize {opcode}'.format(
+            opcode=opcode)
diff --git a/tests/integration/deckard/pydnstest/testserver.py b/tests/integration/deckard/pydnstest/testserver.py
new file mode 100644
index 0000000..5be2959
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/testserver.py
@@ -0,0 +1,309 @@
+import argparse
+import itertools
+import logging
+import os
+import random
+import signal
+import selectors
+import socket
+import sys
+import threading
+import time
+
+import dns.message
+import dns.rdatatype
+
+from pydnstest import scenario, mock_client
+from networking import InterfaceManager
+
+
+class TestServer:
+    """ This simulates UDP DNS server returning scripted or mirror DNS responses. """
+
+    RETRIES_ON_BIND = 3
+
+    def __init__(self, test_scenario, addr_family,
+                 deckard_address=None, if_manager=None):
+        """ Initialize server instance. """
+        self.thread = None
+        self.srv_socks = []
+        self.client_socks = []
+        self.connections = []
+        self.active = False
+        self.active_lock = threading.Lock()
+        self.condition = threading.Condition()
+        self.scenario = test_scenario
+        self.scenario.deckard_address = deckard_address
+        self.addr_map = []
+        self.start_iface = 2
+        self.cur_iface = self.start_iface
+        self.addr_family = addr_family
+        self.undefined_answers = 0
+        self.if_manager = if_manager
+
+    def __del__(self):
+        """ Cleanup after deletion. """
+        with self.active_lock:
+            active = self.active
+        if active:
+            self.stop()
+
+    def start(self):
+        """ Synchronous start """
+        with self.active_lock:
+            if self.active:
+                raise Exception('TestServer already started')
+        with self.active_lock:
+            self.active = True
+
+        self._bind_sockets()
+
+    def stop(self):
+        """ Stop socket server operation. """
+        with self.active_lock:
+            self.active = False
+        if self.thread:
+            self.thread.join()
+        for conn in self.connections:
+            conn.close()
+        for srv_sock in self.srv_socks:
+            srv_sock.close()
+        for client_sock in self.client_socks:
+            client_sock.close()
+        self.client_socks = []
+        self.srv_socks = []
+        self.connections = []
+        self.scenario = None
+
+    def address(self):
+        """ Returns opened sockets list """
+        addrlist = []
+        for s in self.srv_socks:
+            addrlist.append(s.getsockname())
+        return addrlist
+
+    def handle_query(self, client):
+        """
+        Receive query from client socket and send an answer.
+
+        Returns:
+            True if client socket should be closed by caller
+            False if client socket should be kept open
+        """
+        log = logging.getLogger('pydnstest.testserver.handle_query')
+        server_addr = client.getsockname()[0]
+        query, client_addr = mock_client.recvfrom_msg(client)
+        if query is None:
+            return False
+        log.debug('server %s received query from %s: %s', server_addr, client_addr, query)
+
+        message = self.scenario.reply(query, server_addr)
+        if not message:
+            log.debug('ignoring')
+            return True
+        elif isinstance(message, scenario.DNSReplyServfail):
+            self.undefined_answers += 1
+            self.scenario.current_step.log.error(
+                'server %s has no response for question %s, answering with SERVFAIL',
+                server_addr,
+                '; '.join([str(rr) for rr in query.question]))
+        else:
+            log.debug('response: %s', message)
+
+        mock_client.sendto_msg(client, message.to_wire(), client_addr)
+        return True
+
+    def query_io(self):
+        """ Main server process """
+        self.undefined_answers = 0
+        with self.active_lock:
+            if not self.active:
+                raise Exception("[query_io] Test server not active")
+        while True:
+            with self.condition:
+                self.condition.notify()
+            with self.active_lock:
+                if not self.active:
+                    break
+            objects = self.srv_socks + self.connections
+            sel = selectors.DefaultSelector()
+            for obj in objects:
+                sel.register(obj, selectors.EVENT_READ)
+            items = sel.select(0.1)
+            for key, event in items:
+                sock = key.fileobj
+                if event & selectors.EVENT_READ:
+                    if sock in self.srv_socks:
+                        if sock.proto == socket.IPPROTO_TCP:
+                            conn, _ = sock.accept()
+                            self.connections.append(conn)
+                        else:
+                            self.handle_query(sock)
+                    elif sock in self.connections:
+                        if not self.handle_query(sock):
+                            sock.close()
+                            self.connections.remove(sock)
+                    else:
+                        raise Exception(
+                            "[query_io] Socket IO internal error {}, exit"
+                            .format(sock.getsockname()))
+                else:
+                    raise Exception("[query_io] Socket IO error {}, exit"
+                                    .format(sock.getsockname()))
+
+    def start_srv(self, address, family, proto=socket.IPPROTO_UDP):
+        """ Starts listening thread if necessary """
+        assert address
+        assert address[0]  # host
+        assert address[1]  # port
+        assert family
+        assert proto
+        if family == socket.AF_INET6:
+            if not socket.has_ipv6:
+                raise NotImplementedError("[start_srv] IPv6 is not supported by socket {0}"
+                                          .format(socket))
+        elif family != socket.AF_INET:
+            raise NotImplementedError("[start_srv] unsupported protocol family {0}".format(family))
+
+        if proto == socket.IPPROTO_TCP:
+            socktype = socket.SOCK_STREAM
+        elif proto == socket.IPPROTO_UDP:
+            socktype = socket.SOCK_DGRAM
+        else:
+            raise NotImplementedError("[start_srv] unsupported protocol {0}".format(proto))
+
+        if self.thread is None:
+            self.thread = threading.Thread(target=self.query_io)
+            self.thread.start()
+            with self.condition:
+                self.condition.wait()
+
+        for srv_sock in self.srv_socks:
+            if (srv_sock.family == family
+                    and srv_sock.getsockname()[:2] == address
+                    and srv_sock.proto == proto):
+                return
+
+        sock = socket.socket(family, socktype, proto)
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+
+        # Add address to interface when running from Deckard
+        if self.if_manager is not None:
+            if address[0] not in self.if_manager.added_addresses:
+                self.if_manager.add_address(address[0])
+
+        # A lot of addresses are added to the interface while runnning from Deckard in
+        # the small amount of time which caused ocassional hiccups while binding to them
+        # right afterwards in testing. Therefore, we retry a few times.
+        final_ex = None
+        for i in range(self.RETRIES_ON_BIND):
+            try:
+                sock.bind(address)
+                break
+            except OSError as ex:
+                # Exponential backoff
+                time.sleep((2 ** i) + random.random())
+                final_ex = ex
+                continue
+        else:
+            print(final_ex, address)
+            raise final_ex
+
+        if proto == socket.IPPROTO_TCP:
+            sock.listen(5)
+        self.srv_socks.append(sock)
+
+    def _bind_sockets(self):
+        """
+        Bind test server to port 53 on all addresses referenced by test scenario.
+        """
+        # Bind to test servers
+        for r in self.scenario.ranges:
+            for addr in r.addresses:
+                family = socket.AF_INET6 if ':' in addr else socket.AF_INET
+                self.start_srv((addr, 53), family)
+                self.start_srv((addr, 53), family, proto=socket.IPPROTO_TCP)
+
+        # Bind addresses in ad-hoc REPLYs
+        for s in self.scenario.steps:
+            if s.type == 'REPLY':
+                reply = s.data[0].message
+                for rr in itertools.chain(reply.answer,
+                                          reply.additional,
+                                          reply.question,
+                                          reply.authority):
+                    for rd in rr:
+                        if rd.rdtype == dns.rdatatype.A:
+                            self.start_srv((rd.address, 53), socket.AF_INET)
+                            self.start_srv((rd.address, 53), socket.AF_INET,
+                                           proto=socket.IPPROTO_TCP)
+                        elif rd.rdtype == dns.rdatatype.AAAA:
+                            self.start_srv((rd.address, 53), socket.AF_INET6)
+                            self.start_srv((rd.address, 53), socket.AF_INET6,
+                                           proto=socket.IPPROTO_TCP)
+
+    def play(self, subject_addr):
+        self.scenario.play({'': (subject_addr, 53)})
+
+
+def empty_test_case():
+    """
+    Return (scenario, config) pair which answers to any query on 127.0.0.10.
+    """
+    # Mirror server
+    empty_test_path = os.path.dirname(os.path.realpath(__file__)) + "/empty.rpl"
+    test_config = {'ROOT_ADDR': '127.0.0.10',
+                   '_SOCKET_FAMILY': socket.AF_INET}
+    return scenario.parse_file(empty_test_path)[0], test_config
+
+
+def standalone_self_test():
+    """
+    Self-test code
+
+    Usage:
+    unshare -rn $PYTHON -m pydnstest.testserver --help
+    """
+    logging.basicConfig(level=logging.DEBUG)
+    argparser = argparse.ArgumentParser()
+    argparser.add_argument('--scenario', help='absolute path to test scenario',
+                           required=False)
+    argparser.add_argument('--step', help='step # in the scenario (default: first)',
+                           required=False, type=int)
+    args = argparser.parse_args()
+    if args.scenario:
+        test_scenario, test_config_text = scenario.parse_file(args.scenario)
+        test_config = scenario.parse_config(test_config_text, True, os.getcwd())
+    else:
+        test_scenario, test_config = empty_test_case()
+
+    if args.step:
+        for step in test_scenario.steps:
+            if step.id == args.step:
+                test_scenario.current_step = step
+        if not test_scenario.current_step:
+            raise ValueError('step ID %s not found in scenario' % args.step)
+    else:
+        test_scenario.current_step = test_scenario.steps[0]
+
+    if_manager = InterfaceManager(interface="testserver")
+    server = TestServer(test_scenario, test_config['_SOCKET_FAMILY'], if_manager=if_manager)
+    server.start()
+
+    logging.info("[==========] Mirror server running at %s", server.address())
+
+    def kill(signum, frame):  # pylint: disable=unused-argument
+        logging.info("[==========] Shutdown.")
+        server.stop()
+        sys.exit(128 + signum)
+
+    signal.signal(signal.SIGINT, kill)
+    signal.signal(signal.SIGTERM, kill)
+
+    while True:
+        time.sleep(0.5)
+
+
+if __name__ == '__main__':
+    # this is done to avoid creating global variables
+    standalone_self_test()