fix(tests): use delay variables in retry delay test

The delay2 and delay3 variables were calculated but never asserted,
causing lint warnings. Added assertions to verify all delays are
positive and within max bounds.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/services/mcp/test_routing.py

@@ -2,15 +2,13 @@
 Tests for MCP Tool Call Routing
 """
 
-from unittest.mock import AsyncMock, MagicMock, patch
+from unittest.mock import AsyncMock, patch
 
 import pytest
 
 from app.services.mcp.config import MCPConfig, MCPServerConfig
 from app.services.mcp.connection import ConnectionPool
 from app.services.mcp.exceptions import (
-    MCPCircuitOpenError,
-    MCPToolError,
     MCPToolNotFoundError,
 )
 from app.services.mcp.registry import MCPServerRegistry
@@ -79,7 +77,10 @@ class TestToolInfo:
             name="create_issue",
             description="Create a new issue",
             server_name="issues",
-            input_schema={"type": "object", "properties": {"title": {"type": "string"}}},
+            input_schema={
+                "type": "object",
+                "properties": {"title": {"type": "string"}},
+            },
         )
         assert info.name == "create_issue"
         assert info.description == "Create a new issue"
@@ -174,9 +175,7 @@ class TestToolRouter:
 
         # Mock the pool connection and request
         mock_conn = AsyncMock()
-        mock_conn.execute_request = AsyncMock(
-            return_value={"result": {"status": "ok"}}
-        )
+        mock_conn.execute_request = AsyncMock(return_value={"result": {"status": "ok"}})
         mock_conn.is_connected = True
 
         with patch.object(router._pool, "get_connection", return_value=mock_conn):
@@ -232,9 +231,7 @@ class TestToolRouter:
         await router.register_tool_mapping("tool-on-server-1", "server-1")
 
         mock_conn = AsyncMock()
-        mock_conn.execute_request = AsyncMock(
-            return_value={"result": "routed"}
-        )
+        mock_conn.execute_request = AsyncMock(return_value={"result": "routed"})
         mock_conn.is_connected = True
 
         with patch.object(router._pool, "get_connection", return_value=mock_conn):
@@ -339,7 +336,11 @@ class TestToolRouter:
         delay2 = router._calculate_retry_delay(2, config)
         delay3 = router._calculate_retry_delay(3, config)
 
-        # Delays should increase with attempts
+        # All delays should be positive
         assert delay1 > 0
-        # Allow for jitter variation
+        assert delay2 > 0
+        assert delay3 > 0
+        # All delays should be within max bounds (allow for jitter variation)
         assert delay1 <= config.retry_max_delay * 1.25
+        assert delay2 <= config.retry_max_delay * 1.25
+        assert delay3 <= config.retry_max_delay * 1.25