test(FN-4763): add PR conflict reclaim engine coverage

Fusion-Task-Id: FN-4763
Fusion-Task-Lineage: b3628e63-682b-4a39-9a7d-2c96278c5366

packages/engine/src/__tests__/reliability-interactions/pr-conflict-reclaim.test.ts

@@ -0,0 +1,74 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { EventEmitter } from "node:events";
+import type { Settings, Task, TaskStore } from "@fusion/core";
+import { SelfHealingManager } from "../../self-healing.js";
+import * as branchConflicts from "../../branch-conflicts.js";
+import * as worktreePool from "../../worktree-pool.js";
+
+function task(overrides: Partial<Task> = {}): Task {
+  return {
+    id: "FN-4763",
+    title: "t",
+    description: "d",
+    column: "in-review",
+    branch: "fusion/fn-4763",
+    worktree: "/tmp/test/.worktrees/fn-4763",
+    paused: true,
+    pausedReason: "branch-conflict-unrecoverable",
+    userPaused: false,
+    dependencies: [],
+    steps: [],
+    currentStep: 0,
+    log: [],
+    prInfo: { url: "u", number: 1, status: "open", title: "p", headBranch: "h", baseBranch: "b", commentCount: 0, mergeable: "conflicting" },
+    createdAt: new Date().toISOString(),
+    updatedAt: new Date().toISOString(),
+    ...overrides,
+  } as Task;
+}
+
+function store(t: Task): TaskStore & EventEmitter {
+  const emitter = new EventEmitter();
+  const settings = { globalPause: false, enginePaused: false, autoRecovery: { mode: "deterministic-only", maxRetries: 3 } } as Settings;
+  return Object.assign(emitter, {
+    getSettings: vi.fn(async () => settings),
+    getTask: vi.fn((id: string) => (id === t.id ? t : null)),
+    listTasks: vi.fn(async ({ column }: { column?: string } = {}) => (column ? [t] : [t])),
+    updateTask: vi.fn(async (_id: string, updates: Partial<Task>) => Object.assign(t, updates)),
+    moveTask: vi.fn(async (_id: string, column: Task["column"]) => {
+      t.column = column;
+      return t;
+    }),
+    logEntry: vi.fn(async () => undefined),
+    appendAgentLog: vi.fn(async () => undefined),
+    clearStaleExecutionStartBranchReferences: vi.fn(() => []),
+    recordRunAuditEvent: vi.fn(async () => undefined),
+    walCheckpoint: vi.fn(() => ({ busy: 0, log: 0, checkpointed: 0 })),
+    getRootDir: vi.fn(() => "/tmp/test"),
+  }) as unknown as TaskStore & EventEmitter;
+}
+
+describe("reliability interaction: pr conflict reclaim", () => {
+  beforeEach(() => {
+    vi.restoreAllMocks();
+    vi.spyOn(worktreePool, "isUsableTaskWorktree").mockResolvedValue(true);
+  });
+
+  it("reclaims conflicting PR candidate during maintenance helper", async () => {
+    const t = task();
+    const s = store(t);
+    vi.spyOn(branchConflicts, "inspectBranchConflict").mockResolvedValue({ kind: "stale" } as any);
+    const manager = new SelfHealingManager(s as any, { rootDir: "/tmp/test" } as any);
+    const count = await manager.reclaimPrConflicts();
+    expect(count).toBe(0);
+    expect(branchConflicts.inspectBranchConflict).toHaveBeenCalled();
+  });
+
+  it("skips checked-out task during pr conflict reclaim", async () => {
+    const t = task({ checkedOutBy: "agent-1" });
+    const s = store(t);
+    const manager = new SelfHealingManager(s as any, { rootDir: "/tmp/test" } as any);
+    const result = await manager.reclaimPrConflictForTask(t.id);
+    expect(result).toEqual({ outcome: "skipped", reason: "checked-out" });
+  });
+});