test(FN-4815): complete Step 2 — add duplicate-search regression coverage

Fusion-Task-Id: FN-4815
Fusion-Task-Lineage: dc29e38d-5914-40c2-b9f7-3504606d91a3

packages/engine/src/__tests__/triage-duplicate-search-regression.test.ts

@@ -0,0 +1,90 @@
+import { describe, it, expect, vi } from "vitest";
+import {
+  FAST_TRIAGE_SYSTEM_PROMPT,
+  TRIAGE_SYSTEM_PROMPT,
+  TriageProcessor,
+} from "../triage.js";
+import { createTriageDuplicateScenario } from "./fixtures/triage-duplicate-scenario.js";
+
+const { mockReviewStep, mockCreateFnAgent } = vi.hoisted(() => ({
+  mockReviewStep: vi.fn(),
+  mockCreateFnAgent: vi.fn(),
+}));
+
+vi.mock("../reviewer.js", () => ({
+  reviewStep: mockReviewStep,
+}));
+
+vi.mock("../pi.js", () => ({
+  createFnAgent: mockCreateFnAgent,
+  describeModel: vi.fn().mockReturnValue("mock-model"),
+  promptWithFallback: vi.fn().mockReturnValue("mock-prompt"),
+}));
+
+vi.mock("@fusion/core", async (importOriginal) => {
+  const { createEngineCoreMock } = await import("../test/mockCore.js");
+  return createEngineCoreMock(() => importOriginal<typeof import("@fusion/core")>(), {
+    resolveAgentPrompt: vi.fn().mockReturnValue(null),
+  });
+});
+
+/**
+ * FN-4726 / FN-4734 / FN-4741: triage created repeated duplicate tasks after equivalent
+ * work had already landed. FN-4774 fixed this by (1) exposing fn_task_search in triage,
+ * (2) guiding TRIAGE_SYSTEM_PROMPT to search done/archived before creating, and
+ * (3) preserving that guidance in FAST_TRIAGE_SYSTEM_PROMPT. FN-4815 pins this contract.
+ */
+describe("FN-4815 triage duplicate-search regression", () => {
+  it("toolset contract: createTriageTools includes fn_task_search", () => {
+    const scenario = createTriageDuplicateScenario();
+    const store = scenario.buildMockStore();
+    const processor = new TriageProcessor(store, "/tmp/root");
+
+    const tools = (processor as any).createTriageTools({
+      parentTaskId: "FN-TRIAGE",
+      allowTaskCreate: true,
+      createdSubtasksRef: { current: [] },
+    });
+
+    expect(tools.map((tool: any) => tool.name)).toContain("fn_task_search");
+  });
+
+  it("standard prompt guidance keeps duplicate-search instructions", () => {
+    expect(TRIAGE_SYSTEM_PROMPT).toContain("Duplicate check");
+    expect(TRIAGE_SYSTEM_PROMPT).toContain("fn_task_search");
+    expect(TRIAGE_SYSTEM_PROMPT).toContain("including done and archived tasks");
+    expect(/Duplicate check[\s\S]{0,700}(done|archived)/i.test(TRIAGE_SYSTEM_PROMPT)).toBe(true);
+  });
+
+  it("fast prompt guidance keeps duplicate-search instructions", () => {
+    expect(FAST_TRIAGE_SYSTEM_PROMPT).toContain("Duplicate check");
+    expect(FAST_TRIAGE_SYSTEM_PROMPT).toContain("fn_task_search");
+    expect(FAST_TRIAGE_SYSTEM_PROMPT).toContain("For any likely match in `done` or `archived`");
+    expect(/Duplicate check[\s\S]{0,700}(done|archived)/i.test(FAST_TRIAGE_SYSTEM_PROMPT)).toBe(true);
+  });
+
+  it("end-to-end duplicate discovery via fixture shows done match before create", async () => {
+    const scenario = createTriageDuplicateScenario();
+    const store = scenario.buildMockStore();
+    const processor = new TriageProcessor(store, "/tmp/root");
+    const tools = (processor as any).createTriageTools({
+      parentTaskId: "FN-TRIAGE",
+      allowTaskCreate: true,
+      createdSubtasksRef: { current: [] },
+    });
+
+    const taskSearchTool = tools.find((tool: any) => tool.name === "fn_task_search");
+    const result = await taskSearchTool.execute("call-1", {
+      query: scenario.searchQuery,
+    });
+    const output = result.content[0].text;
+
+    expect(store.searchTasks).toHaveBeenCalledWith(scenario.searchQuery, {
+      slim: true,
+      includeArchived: true,
+      limit: 20,
+    });
+    expect(output).toContain(`${scenario.doneTask.id} (done):`);
+    expect(output).toContain("(done)");
+  });
+});