Add unit tests for cleanupStaleTrackedRequests

[Copilot]

cleanupStaleTrackedRequests was exported and designed with a testable now parameter, but had zero test coverage for TTL-based eviction or entry preservation.

Changes

• background.js — Extends module.exports to expose cleanupStaleTrackedRequests, initialHostByRequest, redirectedRequestIds, and REQUEST_TRACK_TTL_MS for test access.

• tests/cleanup.test.js — New test suite with four deterministic scenarios driven by a fixed now value:

  • Stale entries (beyond TTL) evicted from initialHostByRequest
  • Fresh entries (within TTL) preserved
  • Eviction removes the requestId from redirectedRequestIds in sync
  • No-op and no throw on empty map

test("removes entries older than TTL", () => {
  const now = 1_000_000;
  initialHostByRequest.set("req-1", { host: "example.com", trackedAt: now - REQUEST_TRACK_TTL_MS - 1 });
  cleanupStaleTrackedRequests(now);
  expect(initialHostByRequest.has("req-1")).toBe(false);
});

Original prompt

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This section details on the original issue you should resolve

<issue_title>[PATCH] cleanupStaleTrackedRequests is exported but has no unit tests</issue_title>
<issue_description>Category: testing
Severity: patch
File(s): background.js, tests/

Description

The function cleanupStaleTrackedRequests is a pure, deterministic utility that accepts an optional now timestamp parameter specifically to facilitate testing. Despite this design, no unit tests cover its behaviour: neither the TTL-based eviction of stale entries from initialHostByRequest and redirectedRequestIds, nor the preservation of entries that are still within the TTL window.

Problematic code example

// background.js
const cleanupStaleTrackedRequests = (now = Date.now()) => {
  for (const [requestId, trackedRequest] of initialHostByRequest.entries()) {
    if (trackedRequest && typeof trackedRequest === "object" && now - trackedRequest.trackedAt > REQUEST_TRACK_TTL_MS) {
      initialHostByRequest.delete(requestId);
      redirectedRequestIds.delete(requestId);
    }
  }
};
// No test file exercises this function

Suggested fix

Add a dedicated test file (e.g. tests/cleanup.test.js) that covers the following scenarios:

const { cleanupStaleTrackedRequests } = require("../background.js");

describe("cleanupStaleTrackedRequests", () => {
  test("removes entries older than TTL", () => { /* ... */ });
  test("preserves entries within TTL", () => { /* ... */ });
  test("also removes requestId from redirectedRequestIds", () => { /* ... */ });
  test("no-op on empty map", () => { /* ... */ });
});

Acceptance criteria

• A test file exists for cleanupStaleTrackedRequests
• Stale entries (beyond TTL) are evicted from both initialHostByRequest and redirectedRequestIds
• Fresh entries (within TTL) are preserved
• The empty-map case is covered</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [PATCH] cleanupStaleTrackedRequests is exported but has no unit tests #187

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[Copilot]

Pull request overview

Adds deterministic Jest unit tests for cleanupStaleTrackedRequests to validate TTL-based eviction behavior and ensure tracking state stays consistent across internal data structures.

Changes:

• Export cleanupStaleTrackedRequests and its related in-memory tracking structures/constants from background.js for test access.
• Add tests/cleanup.test.js covering stale eviction, fresh preservation, synced cleanup of redirectedRequestIds, and empty-map no-op behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
background.js	Extends module.exports to expose the cleanup helper plus its associated Maps/Sets and TTL constant to Jest.
tests/cleanup.test.js	New deterministic unit tests for TTL eviction and state synchronization using a fixed now timestamp.

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