fix: name and version from system_information; a CARP address on its MASTER's interface

get_facts read hostname and version from /api/core/system/status, which on
OPNsense 26.7 carries neither: every firewall read as nameless and "unknown",
and netOrk kept naming one by its address. /api/diagnostics/system/system_information
has both (name is the FQDN, versions[0] "OPNsense 26.7.7-amd64"). The status
answer still counts where the new one gives nothing.

get_interfaces_ip listed each interface's primary address only, so a CARP address
never showed as the holder's. It now lists an address bound to a VHID on the node
that is MASTER for it, and leaves it off a BACKUP -- as keepalived puts the address
on the master alone. netOrk's VIP badge sits on that interface (netOrk #1121).

tests/unit/test_identity_and_held_addresses.py

@@ -0,0 +1,132 @@
+"""What the firewall is called, which version it runs, and which addresses it serves.
+
+``/api/core/system/status`` on OPNsense 26.7 carries neither name nor version
+(``metadata`` and ``subsystems`` only), so every firewall read as nameless and
+"unknown". ``/api/diagnostics/system/system_information`` has both: ``name`` is
+the FQDN, ``versions[0]`` reads ``"OPNsense 26.7.7-amd64"``.
+
+An address bound to a CARP VHID sits on the interface of every node, in state
+MASTER or BACKUP. Only the MASTER answers for it, so only there is it one of the
+node's addresses -- the same as keepalived, where only the master has the address
+at all (netOrk #1121: a virtual IP's badge sits on its holder's interface).
+"""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from napalm_opnsense.opnsense import OPNsenseDriver
+
+OVERVIEW = json.loads(
+    (Path(__file__).parent / "fixtures" / "interfaces_overview_carp.json").read_text()
+)
+SYSTEM_INFORMATION = {
+    "name": "gw-02.home.manivong.de",
+    "versions": ["OPNsense 26.7.7-amd64", "FreeBSD 15.1-RELEASE-p4", "OpenSSL 3.5.9"],
+}
+STATUS_26_7 = {"metadata": {"translations": {}}, "subsystems": {}}
+
+
+@pytest.fixture
+def driver() -> OPNsenseDriver:
+    with patch("napalm_opnsense.opnsense.requests.Session"):
+        return OPNsenseDriver(hostname="fw", username="k", password="s")
+
+
+def _answers(driver, system_information=SYSTEM_INFORMATION, status=STATUS_26_7, overview=OVERVIEW):
+    def get(path: str):
+        if path == "/api/diagnostics/system/system_information":
+            if isinstance(system_information, Exception):
+                raise system_information
+            return system_information
+        if path == "/api/core/system/status":
+            return status
+        if path == "/api/interfaces/overview/export":
+            return overview
+        raise AssertionError(f"unexpected GET {path}")
+
+    driver._get = get
+    return driver
+
+
+class TestIdentity:
+    def test_the_name_is_the_short_host_and_the_fqdn_the_whole(self, driver):
+        facts = _answers(driver).get_facts()
+        assert (facts["hostname"], facts["fqdn"]) == ("gw-02", "gw-02.home.manivong.de")
+
+    def test_the_version_comes_without_the_architecture(self, driver):
+        assert _answers(driver).get_facts()["os_version"] == "26.7.7"
+
+    @pytest.mark.parametrize(
+        "line, version",
+        [
+            ("OPNsense 26.7.7_1-aarch64", "26.7.7_1"),
+            ("OPNsense 25.1", "25.1"),
+            ("OPNsense 24.7.12-i386", "24.7.12"),
+        ],
+    )
+    def test_version_spellings(self, driver, line, version):
+        info = {"name": "fw", "versions": [line]}
+        assert _answers(driver, system_information=info).get_facts()["os_version"] == version
+
+    def test_a_name_without_a_domain_is_both(self, driver):
+        facts = _answers(driver, system_information={"name": "fw", "versions": []}).get_facts()
+        assert (facts["hostname"], facts["fqdn"]) == ("fw", "fw")
+
+    def test_without_system_information_the_status_answer_still_counts(self, driver):
+        """An older OPNsense, or an API key without the diagnostics privilege."""
+        status = {"hostname": "opnsense01", "version": "24.7"}
+        facts = _answers(driver, system_information=RuntimeError("403"), status=status).get_facts()
+        assert (facts["hostname"], facts["os_version"]) == ("opnsense01", "24.7")
+
+    def test_nothing_known_is_empty_and_unknown(self, driver):
+        facts = _answers(driver, system_information={}).get_facts()
+        assert (facts["hostname"], facts["fqdn"], facts["os_version"]) == ("", "", "unknown")
+
+
+class TestHeldAddresses:
+    def test_the_master_serves_its_carp_addresses(self, driver):
+        result = _answers(driver).get_interfaces_ip()
+        assert set(result["em0"]["ipv4"]) == {"192.0.2.2", "192.0.2.1"}
+        assert result["em0"]["ipv4"]["192.0.2.1"] == {"prefix_length": 24}
+        assert set(result["vlan0040"]["ipv4"]) == {
+            "198.51.100.2",
+            "198.51.100.1",
+            "198.51.100.140",
+        }
+
+    def test_a_backup_serves_its_own_address_only(self, driver):
+        backup = json.loads(json.dumps(OVERVIEW).replace('"MASTER"', '"BACKUP"'))
+        result = _answers(driver, overview=backup).get_interfaces_ip()
+        assert set(result["em0"]["ipv4"]) == {"192.0.2.2"}
+        assert set(result["vlan0040"]["ipv4"]) == {"198.51.100.2"}
+
+    def test_a_vhid_that_is_not_up_is_not_served(self, driver):
+        result = _answers(driver).get_interfaces_ip()
+        assert set(result["vlan0011"]["ipv4"]) == {"203.0.113.2"}
+
+    def test_a_held_ipv6_carp_address_is_served(self, driver):
+        result = _answers(driver).get_interfaces_ip()
+        assert "2001:db8:8::1" in result["em0"]["ipv6"]
+
+    def test_an_address_without_a_vhid_is_left_as_before(self, driver):
+        """Only CARP addresses are added; a plain alias is a separate question."""
+        result = _answers(driver).get_interfaces_ip()
+        assert set(result["vlan0020"]["ipv4"]) == {"192.0.2.130"}
+
+    def test_without_a_primary_address_the_list_still_leaves_out_a_backup(self, driver):
+        overview = [
+            {
+                "device": "vlan0099",
+                "ipv4": [
+                    {"ipaddr": "192.0.2.66/26"},
+                    {"ipaddr": "192.0.2.65/26", "vhid": "199", "status": "BACKUP"},
+                ],
+            }
+        ]
+        result = _answers(driver, overview=overview).get_interfaces_ip()
+        assert set(result["vlan0099"]["ipv4"]) == {"192.0.2.66"}