feat: get_system_identity for matching a host to its BMC (0.7.0)

Mixes in napalm-device-types 4.9's SystemIdentityMixin: the host's
SMBIOS system UUID, product serial and board serial, read as root on an
exec channel, vendor placeholders empty. netOrk links a server's BMC to
the host on these.

tests/test_linux.py

@@ -1725,6 +1725,39 @@ class TestGetListeningSockets:
         assert plain.startswith("sh -c '")
 
 
+# ---------------------------------------------------------------------------
+# get_system_identity (napalm-device-types SystemIdentityMixin)
+# ---------------------------------------------------------------------------
+
+
+class TestGetSystemIdentity:
+    """What ties a host to its BMC: SMBIOS UUID and serials, read as root on an exec
+    channel (product_uuid and product_serial are root's)."""
+
+    def test_it_reads_the_shared_command_as_root_on_an_exec_channel(self, driver):
+        from napalm_device_types import SYSTEM_IDENTITY_COMMAND, CommandResult, SystemIdentityMixin
+
+        assert isinstance(driver, SystemIdentityMixin)
+        calls = []
+
+        def run_command(command, *, privileged=False, timeout=60, stdin=None):
+            calls.append((command, privileged))
+            out = "IDBEGIN\n31303043-534D-C40C-7A72-6F1300000000\n0123456789\nZM155S026022\nIDEND\n"
+            return CommandResult(out, "", 0)
+
+        driver.run_command = run_command
+
+        identity = driver.get_system_identity()
+
+        assert identity == {
+            "system_uuid": "31303043-534d-c40c-7a72-6f1300000000",
+            "product_serial": "",  # Supermicro's placeholder
+            "board_serial": "ZM155S026022",
+        }
+        assert calls == [(SYSTEM_IDENTITY_COMMAND, True)]
+        driver._device.send_command.assert_not_called()
+
+
 # ---------------------------------------------------------------------------
 # get_virtual_ips (napalm-device-types VirtualIpsMixin)
 # ---------------------------------------------------------------------------