test(FN-4296): repro — durable agent retains stale taskId for queued/done task

Fusion-Task-Id: FN-4296
Fusion-Task-Lineage: 9d061861-547a-4905-8fdd-4b66dd7bff97

packages/engine/src/__tests__/self-healing-agent-link-drift.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it, vi } from "vitest";
+
+import type { Agent, Task } from "@fusion/core";
+import type { AgentStore } from "@fusion/core";
+
+import { SelfHealingManager } from "../self-healing";
+
+describe("FN-4296: self-healing agent link drift repro", () => {
+  it("FN-4296: durable running agent linked to done task remains stale before fix", async () => {
+    const agents: Agent[] = [
+      {
+        id: "agent-Y",
+        state: "running",
+        taskId: "FN-X",
+        updatedAt: new Date(Date.now() - 120_000).toISOString(),
+      } as Agent,
+    ];
+
+    const store = {
+      getTask: vi.fn(async (taskId: string) => (taskId === "FN-X" ? ({ id: "FN-X", column: "done" } as Task) : null)),
+    } as any;
+
+    const agentStore = {
+      listAgents: vi.fn(async () => agents),
+      getActiveHeartbeatRun: vi.fn(async () => null),
+      updateAgentState: vi.fn(async () => undefined),
+      syncExecutionTaskLink: vi.fn(async (agentId: string, taskId?: string) => {
+        const agent = agents.find((candidate) => candidate.id === agentId);
+        if (agent) agent.taskId = taskId;
+      }),
+    } as unknown as AgentStore;
+
+    const manager = new SelfHealingManager(store, { rootDir: "/tmp/test-project", agentStore });
+
+    await manager.recoverAgentsRunningOnInactiveTasks();
+
+    expect(agents[0].taskId).toBeUndefined();
+
+    manager.stop();
+  });
+});