test(mcp): cover timer shutdown scheduling guards

features/steps/tdd_mcp_client_timer_cancel_race_steps.py

@@ -88,6 +88,35 @@ def step_shared_callback_flag(context: Context) -> None:
     context.timer_race_callback_lock = threading.Lock()
 
 
+@given("an McpClient with active idle and health timers")
+def step_mcp_client_active_timers(context: Context) -> None:
+    """Create a client whose timer schedulers would normally install timers."""
+    server_config = MCPServerConfig(
+        name="test-timer-shutdown-guard",
+        transport="stdio",
+        command="echo",
+    )
+    context.timer_race_config = McpClientConfig(
+        server=server_config,
+        lazy_start=False,
+        idle_timeout_seconds=60.0,
+        health_check_interval_seconds=60.0,
+    )
+    context.timer_race_transport = MockMCPTransport(
+        tools=[_mock_tool("test_tool")],
+    )
+    context.timer_race_client = McpClient(
+        config=context.timer_race_config,
+        transport=context.timer_race_transport,
+    )
+
+
+@given("the timer race client is marked as shutting down")
+def step_mark_timer_race_client_shutting_down(context: Context) -> None:
+    """Simulate the shutdown window before timer scheduling is attempted."""
+    context.timer_race_client._shutting_down = True
+
+
 # ── When ──────────────────────────────────────────────────────────
 
 
@@ -213,6 +242,13 @@ def step_wait_for_late_fires(context: Context) -> None:
     original_sleep(0.3)
 
 
+@when("I ask the client to schedule idle and health timers")
+def step_schedule_idle_and_health_timers(context: Context) -> None:
+    """Invoke both scheduler guards while shutdown is in progress."""
+    context.timer_race_client._schedule_idle_timer()
+    context.timer_race_client._schedule_health_check()
+
+
 # ── Then ──────────────────────────────────────────────────────────
 
 
@@ -237,3 +273,11 @@ def step_idle_callback_not_fired_after_shutdown(context: Context) -> None:
         "different synchronisation scheme to prevent the race. "
         f"Errors (if any): {getattr(context, 'timer_race_errors', [])}"
     )
+
+
+@then("no idle or health timer should be scheduled")
+def step_no_idle_or_health_timer_scheduled(context: Context) -> None:
+    """Assert shutdown guards returned before installing timers."""
+    client = context.timer_race_client
+    assert client._idle_timer is None, "Idle timer was scheduled during shutdown"
+    assert client._health_timer is None, "Health timer was scheduled during shutdown"

features/tdd_mcp_client_timer_cancel_race.feature

@@ -75,4 +75,10 @@ Feature: TDD Issue #10516 — McpClient timer can fire after cancellation race
     When I start the client
     And I trigger the idle timer race by forcing a reschedule during shutdown
     And I wait long enough for any late timer fires (0.3s)
-    Then the idle timer callback should not have fired after shutdown
+    Then the idle timer callback should not have fired after shutdown
+
+  Scenario: Timer schedulers skip work during shutdown
+    Given an McpClient with active idle and health timers
+    And the timer race client is marked as shutting down
+    When I ask the client to schedule idle and health timers
+    Then no idle or health timer should be scheduled