test(FN-5152): complete Step 6 — add near-duplicate reliability interaction tests

Fusion-Task-Id: FN-5152
Fusion-Task-Lineage: 954570d8-82e1-4519-a739-c52ee790d2db

packages/engine/src/__tests__/reliability-interactions/near-duplicate-intake.test.ts

@@ -0,0 +1,151 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { mkdtemp, rm } from "node:fs/promises";
+import { execSync } from "node:child_process";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { DEFAULT_SETTINGS, TaskStore } from "@fusion/core";
+import * as core from "@fusion/core";
+import { TriageProcessor } from "../../triage.js";
+
+function git(cwd: string, command: string): string {
+  return execSync(command, { cwd, encoding: "utf-8", stdio: ["pipe", "pipe", "pipe"] }).trim();
+}
+
+async function createFixture() {
+  const rootDir = await mkdtemp(join(tmpdir(), "fusion-near-dup-"));
+  git(rootDir, "git init -b main");
+  git(rootDir, 'git config user.email "test@example.com"');
+  git(rootDir, 'git config user.name "Test User"');
+  git(rootDir, "git commit --allow-empty -m init");
+
+  const store = new TaskStore(rootDir, undefined, { inMemoryDb: true });
+  await store.init();
+  await store.updateSettings({ ...DEFAULT_SETTINGS, requirePlanApproval: false });
+  const triage = new TriageProcessor(store, rootDir);
+
+  return {
+    rootDir,
+    store,
+    triage,
+    cleanup: async () => {
+      store.close();
+      await rm(rootDir, { recursive: true, force: true });
+    },
+  };
+}
+
+const basePrompt = `# Task: FN-1 - test\n\n**Size:** S\n\n## Review Level: 1\n\n## File Scope\n- packages/dashboard/src/routes/register-git-github.ts\n`;
+
+describe("reliability interactions: near-duplicate intake", () => {
+  const fixtures: Array<Awaited<ReturnType<typeof createFixture>>> = [];
+  afterEach(async () => {
+    vi.useRealTimers();
+    vi.restoreAllMocks();
+    while (fixtures.length) await fixtures.pop()!.cleanup();
+  });
+
+  it("archives newer task as near-duplicate and records activity", async () => {
+    const fx = await createFixture();
+    fixtures.push(fx);
+
+    await fx.store.createTask({
+      title: "Create PR routes missing handlers",
+      description: "Missing /api/tasks/:id/pr/options and /api/tasks/:id/pr/preflight and /api/tasks/:id/pr/generate-metadata",
+      column: "todo",
+    });
+    const incoming = await fx.store.createTask({
+      title: "Missing handlers for create PR routes",
+      description: "GET /api/tasks/:id/pr/options and GET /api/tasks/:id/pr/preflight and POST /api/tasks/:id/pr/generate-metadata all fail",
+    });
+
+    await (fx.triage as any).finalizeApprovedTask(incoming, basePrompt, await fx.store.getSettings(), {});
+
+    const updated = await fx.store.getTask(incoming.id);
+    expect(updated.column).toBe("archived");
+    expect(updated.sourceMetadata?.nearDuplicateOf).toBeTruthy();
+    const activity = await fx.store.getActivityLog({ type: "task:auto-archived-near-duplicate", limit: 20 });
+    expect(activity.some((entry) => entry.taskId === incoming.id)).toBe(true);
+  });
+
+  it("does not archive generic file overlap only", async () => {
+    const fx = await createFixture();
+    fixtures.push(fx);
+
+    await fx.store.createTask({
+      title: "Fix PR comments pagination",
+      description: "Touch register-git-github.ts pagination only",
+      column: "todo",
+    });
+    const incoming = await fx.store.createTask({
+      title: "Add PR merge auto-rebase option",
+      description: "Touch register-git-github.ts merge behavior only",
+    });
+
+    await (fx.triage as any).finalizeApprovedTask(incoming, basePrompt, await fx.store.getSettings(), {});
+    const updated = await fx.store.getTask(incoming.id);
+    expect(updated.column).toBe("todo");
+  });
+
+  it("does not archive when candidate is older than window", async () => {
+    vi.useFakeTimers();
+    const fx = await createFixture();
+    fixtures.push(fx);
+
+    vi.setSystemTime(new Date("2026-05-01T00:00:00.000Z"));
+    await fx.store.createTask({
+      title: "Create PR routes missing handlers",
+      description: "Missing /api/tasks/:id/pr/options and /api/tasks/:id/pr/preflight and /api/tasks/:id/pr/generate-metadata",
+      column: "todo",
+    });
+
+    vi.setSystemTime(new Date("2026-05-10T00:00:00.000Z"));
+    const incoming = await fx.store.createTask({
+      title: "Missing handlers for create PR routes",
+      description: "GET /api/tasks/:id/pr/options and GET /api/tasks/:id/pr/preflight and POST /api/tasks/:id/pr/generate-metadata all fail",
+    });
+    await (fx.triage as any).finalizeApprovedTask(incoming, basePrompt, await fx.store.getSettings(), {});
+    const updated = await fx.store.getTask(incoming.id);
+    expect(updated.column).toBe("todo");
+    vi.useRealTimers();
+  });
+
+  it("fails open when extractor throws", async () => {
+    const fx = await createFixture();
+    fixtures.push(fx);
+
+    const incoming = await fx.store.createTask({
+      title: "Missing handlers for create PR routes",
+      description: "GET /api/tasks/:id/pr/options and GET /api/tasks/:id/pr/preflight and POST /api/tasks/:id/pr/generate-metadata all fail",
+    });
+    vi.spyOn(core, "extractIntentSignature").mockImplementation(() => {
+      throw new Error("boom");
+    });
+
+    await (fx.triage as any).finalizeApprovedTask(incoming, basePrompt, await fx.store.getSettings(), {});
+    const updated = await fx.store.getTask(incoming.id);
+    expect(updated.column).toBe("todo");
+  });
+
+  it("does not archive older task when newer candidate exists", async () => {
+    const fx = await createFixture();
+    fixtures.push(fx);
+
+    const older = await fx.store.createTask({
+      title: "Create PR routes missing handlers",
+      description: "Missing /api/tasks/:id/pr/options and /api/tasks/:id/pr/preflight and /api/tasks/:id/pr/generate-metadata",
+    });
+    const newer = await fx.store.createTask({
+      title: "Missing handlers for create PR routes",
+      description: "GET /api/tasks/:id/pr/options and GET /api/tasks/:id/pr/preflight and POST /api/tasks/:id/pr/generate-metadata all fail",
+      column: "todo",
+    });
+
+    await (fx.triage as any).finalizeApprovedTask(older, basePrompt, await fx.store.getSettings(), {});
+
+    const updatedOlder = await fx.store.getTask(older.id);
+    expect(updatedOlder.column).not.toBe("archived");
+    expect(updatedOlder.column).toBe("todo");
+    const updatedNewer = await fx.store.getTask(newer.id);
+    expect(updatedNewer.column).toBe("todo");
+  });
+});