fix(lint): remove unused imports, fix E701 inline-if in test_snmp_collector

Resolves ruff failures on CI:
- Remove unused imports: json, call, pytest, _http_get_json, _http_post_json
- Expand inline if/return to multi-line (E701)
- Remove unused variable if_mac in test_interface_down_status (F841)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AbfhpQR6qzZAXcTacEcZvn

Author: claude

tests/test_snmp_collector.py

@@ -6,12 +6,9 @@
 """
 from __future__ import annotations
 
-import json
 import sys
 import types
-from unittest.mock import MagicMock, patch, call
-
-import pytest
+from unittest.mock import MagicMock, patch
 
 # ---------------------------------------------------------------------------
 # Synthetic pysnmp stub so the import inside snmp_collector doesn't fail
@@ -68,8 +65,6 @@ def _make_pysnmp_stub() -> types.ModuleType:
     _poll_device,
     _vendor_from_sysoid,
     _extract_model_from_descr,
-    _http_get_json,
-    _http_post_json,
     OID_IF_DESCR,
     OID_IF_OPER_STATUS,
     OID_IF_PHY_ADDRESS,
@@ -222,9 +217,12 @@ def test_interfaces_parsed_from_walk(self):
         session.get.return_value = sys_data
 
         def walk_side(oid):
-            if oid == OID_IF_DESCR:       return if_descr
-            if oid == OID_IF_OPER_STATUS:  return if_oper
-            if oid == OID_IF_PHY_ADDRESS:  return if_mac
+            if oid == OID_IF_DESCR:
+                return if_descr
+            if oid == OID_IF_OPER_STATUS:
+                return if_oper
+            if oid == OID_IF_PHY_ADDRESS:
+                return if_mac
             return {}
 
         session.walk.side_effect = walk_side
@@ -240,15 +238,16 @@ def test_interface_down_status(self):
         sys_data = {".1.3.6.1.2.1.1.5.0": "sw"}
         if_descr  = {".1.3.6.1.2.1.2.2.1.2.2": "Ethernet0/1"}
         if_oper   = {".1.3.6.1.2.1.2.2.1.8.2": "2"}  # down
-        if_mac    = {}
 
         session = MagicMock(spec=_SNMPSession)
         session.available = True
         session.get.return_value = sys_data
 
         def walk_side(oid):
-            if oid == OID_IF_DESCR:      return if_descr
-            if oid == OID_IF_OPER_STATUS: return if_oper
+            if oid == OID_IF_DESCR:
+                return if_descr
+            if oid == OID_IF_OPER_STATUS:
+                return if_oper
             return {}
         session.walk.side_effect = walk_side