[nexus] migrate SRP many services MTU test to Nexus (#12948)

This commit migrates the test_srp_many_services_mtu_check.py from
tests/scripts/thread-cert to the Nexus test framework.

The new test, tests/nexus/test_srp_many_services_mtu_check.cpp,
verifies that the SRP client correctly handles and splits SRP Update
messages when registering a large number of services that exceed
the IPv6 MTU size (1280 bytes).

Changes:
- Added tests/nexus/test_srp_many_services_mtu_check.cpp.
- Updated tests/nexus/CMakeLists.txt to include the new test.
- Removed tests/scripts/thread-cert/test_srp_many_services_mtu_check.py.

tests/scripts/thread-cert/test_srp_many_services_mtu_check.py

@@ -1,141 +0,0 @@
-#!/usr/bin/env python3
-#
-#  Copyright (c) 2022, 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 ipaddress
-import unittest
-
-import command
-import config
-import thread_cert
-
-# Test description:
-#
-#   This test verifies SRP client behavior when there are many services
-#   causing SRP Update message going over the IPv6 MTU size. In such
-#   a case the SRP client attempts to register a single service at
-#   a time.
-#
-# Topology:
-#
-#     LEADER (SRP server)
-#       |
-#       |
-#     ROUTER (SRP client)
-#
-
-SERVER = 1
-CLIENT = 2
-
-
-class SrpManyServicesMtuCheck(thread_cert.TestCase):
-    USE_MESSAGE_FACTORY = False
-    SUPPORT_NCP = False
-
-    TOPOLOGY = {
-        SERVER: {
-            'name': 'SRP_SERVER',
-            'mode': 'rdn',
-        },
-        CLIENT: {
-            'name': 'SRP_CLIENT',
-            'mode': 'rdn',
-        },
-    }
-
-    def test(self):
-        server = self.nodes[SERVER]
-        client = self.nodes[CLIENT]
-
-        # Start the server & client devices.
-
-        server.start()
-        self.simulator.go(config.LEADER_STARTUP_DELAY)
-        self.assertEqual(server.get_state(), 'leader')
-
-        client.start()
-        self.simulator.go(config.ROUTER_STARTUP_DELAY)
-        self.assertEqual(client.get_state(), 'router')
-
-        server.srp_server_set_enabled(True)
-        client.srp_client_enable_auto_start_mode()
-        self.simulator.go(15)
-
-        # Register 8 services with long name, 6 sub-types and long txt record.
-        # The 8 services won't be fit in a single MTU (1280 bytes) UDP message
-        # SRP Client would then register services one by one.
-
-        num_services = 8
-
-        client.srp_client_set_host_name('hosthosthosthosthosthosthosthosthosthosthosthosthosthosthosthos')
-        client.srp_client_set_host_address('2001::1')
-
-        txt_info = ["xyz=987654321", "uvw=abcdefghijklmnopqrstu", "qwp=564321abcdefghij"]
-
-        for num in range(num_services):
-            name = chr(ord('a') + num) * 63
-            client.srp_client_add_service(
-                name,
-                '_longlongsrvname._udp,_subtype1,_subtype2,_subtype3,_subtype4,_subtype5,_subtype6',
-                1977,
-                txt_entries=txt_info)
-
-        self.simulator.go(10)
-
-        # Make sure all services are successfully registered
-        # (from both client and server perspectives).
-
-        client_services = client.srp_client_get_services()
-        self.assertEqual(len(client_services), num_services)
-
-        for service in client_services:
-            self.assertEqual(service['state'], 'Registered')
-
-        server_services = server.srp_server_get_services()
-        self.assertEqual(len(server_services), num_services)
-
-        # Remove all 8 services.
-
-        for num in range(num_services):
-            name = chr(ord('a') + num) * 63
-            client.srp_client_remove_service(name, '_longlongsrvname._udp')
-
-        self.simulator.go(10)
-
-        client_services = client.srp_client_get_services()
-        self.assertEqual(len(client_services), 0)
-
-        server_services = server.srp_server_get_services()
-        self.assertEqual(len(server_services), num_services)
-
-        for service in server_services:
-            self.assertEqual(service['deleted'], 'true')
-
-
-if __name__ == '__main__':
-    unittest.main()