tests: Check if we can use solo with a peer-group

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

tests/topotests/bgp_peer_group_solo/r1/frr.conf

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+!
+int r1-eth0
+ ip address 192.168.1.1/24
+!
+int r1-eth1
+ ip address 192.168.14.1/24
+!
+router bgp 65001
+ no bgp ebgp-requires-policy
+ no bgp network import-check
+ neighbor pg peer-group
+ neighbor pg remote-as external
+ neighbor pg solo
+ neighbor pg timers 1 3
+ neighbor pg timers connect 1
+ neighbor 192.168.1.2 peer-group pg
+ neighbor 192.168.1.3 peer-group pg
+ address-family ipv4 unicast
+  network 10.0.0.1/32
+ exit-address-family
+!

tests/topotests/bgp_peer_group_solo/r2/frr.conf

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+!
+int r2-eth0
+ ip address 192.168.1.2/24
+!
+router bgp 65002
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external
+ neighbor 192.168.1.1 timers 1 3
+ neighbor 192.168.1.1 timers connect 1
+!

tests/topotests/bgp_peer_group_solo/r3/frr.conf

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+!
+int r3-eth0
+ ip address 192.168.1.3/24
+!
+router bgp 65003
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external
+ neighbor 192.168.1.1 timers 1 3
+ neighbor 192.168.1.1 timers connect 1
+!

tests/topotests/bgp_peer_group_solo/test_bgp_peer_group_solo.py

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+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2024 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+import os
+import re
+import sys
+import json
+import pytest
+import functools
+
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+
+# pylint: disable=C0413
+from lib import topotest
+from lib.topogen import Topogen, get_topogen
+
+pytestmark = [pytest.mark.bgpd]
+
+
+def setup_module(mod):
+    topodef = {"s1": ("r1", "r2", "r3")}
+    tgen = Topogen(topodef, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for _, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_frr_config(os.path.join(CWD, "{}/frr.conf".format(rname)))
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_remote_as_auto():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+
+    def _bgp_converge():
+        output = json.loads(r1.vtysh_cmd("show bgp ipv4 unicast summary json"))
+        expected = {
+            "peers": {
+                "192.168.1.2": {
+                    "remoteAs": 65002,
+                    "state": "Established",
+                    "peerState": "OK",
+                },
+                "192.168.1.3": {
+                    "remoteAs": 65003,
+                    "state": "Established",
+                    "peerState": "OK",
+                },
+            },
+            "totalPeers": 2,
+        }
+
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_converge,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Can't converge initial state"
+
+    def _bgp_update_groups():
+        actual = []
+        output = json.loads(r1.vtysh_cmd("show bgp ipv4 unicast update-groups json"))
+        expected = [
+            {"subGroup": [{"adjListCount": 1, "peers": ["192.168.1.2"]}]},
+            {"subGroup": [{"adjListCount": 1, "peers": ["192.168.1.3"]}]},
+        ]
+
+        # update-group's number can be random and it's not deterministic,
+        # so we need to normalize the data a bit before checking.
+        # We care here about the `peers` array only actually.
+        for updgrp in output["default"].keys():
+            actual.append(output["default"][updgrp])
+
+        return topotest.json_cmp(actual, expected)
+
+    test_func = functools.partial(
+        _bgp_update_groups,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Can't see separate update-groups"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))