[pktverify] verify offline test info (#5525)

This commit allows running packet verification on a test info (.json)
directly without running the test procedure, which can be helpful for
developing and debugging packet verification code.

script/test

@@ -294,6 +294,11 @@ do_build_otbr_docker()
     rm -rf "${otbrdir}"
 }
 
+do_pktverify()
+{
+    python3 ./tests/scripts/thread-cert/pktverify/verify.py "$1"
+}
+
 do_expect()
 {
     local ot_command
@@ -523,6 +528,10 @@ main()
             build_otbr_docker)
                 do_build_otbr_docker
                 ;;
+            pktverify)
+                shift
+                do_pktverify "$1"
+                ;;
             unit)
                 do_unit
                 ;;

tests/scripts/thread-cert/pktverify/verify.py

@@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+#
+#  Copyright (c) 2020, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+import importlib.util
+import inspect
+import json
+import logging
+import os
+import sys
+
+THREAD_CERT_DIR = './tests/scripts/thread-cert'
+sys.path.append(THREAD_CERT_DIR)
+
+import thread_cert
+from pktverify.packet_verifier import PacketVerifier
+
+logging.basicConfig(level=logging.INFO,
+                    format='File "%(pathname)s", line %(lineno)d, in %(funcName)s\n'
+                    '%(asctime)s - %(levelname)s - %(message)s')
+
+
+def main():
+    json_file = sys.argv[1]
+    with open(json_file, 'rt') as fp:
+        test_info = json.load(fp)
+
+    script = test_info['script']
+
+    script = os.path.relpath(script, THREAD_CERT_DIR)
+
+    module_name = os.path.splitext(script)[0].replace('/', '.')
+    logging.info("Loading %s as module %s ...", script, module_name)
+
+    spec = importlib.util.spec_from_file_location(module_name, os.path.join(THREAD_CERT_DIR, script))
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+
+    test_class = None
+
+    for name, member in inspect.getmembers(mod):
+        if isinstance(member, type) and issubclass(member, thread_cert.TestCase):
+            assert test_class is None, (test_class, member)
+            test_class = member
+
+    assert test_class is not None, "can not find a test class in %s" % script
+
+    test_instance = test_class()
+
+    pv = PacketVerifier(json_file)
+    pv.add_common_vars()
+    test_instance.verify(pv)
+
+    print("Packet verification passed: %s" % json_file, file=sys.stderr)
+
+
+if __name__ == '__main__':
+    main()

tests/scripts/thread-cert/thread_cert.py

@@ -348,6 +348,7 @@ class TestCase(NcpSupportMixin, unittest.TestCase):
             return
 
         test_info = self._test_info = {
+            'script': os.path.abspath(sys.argv[0]),
             'testcase': self.test_name,
             'start_time': time.ctime(self._start_time),
             'pcap': '',