claude-code-action/test/image-downloader.test.ts

import {
  describe,
  test,
  expect,
  spyOn,
  beforeEach,
  afterEach,
  jest,
  setSystemTime,
} from "bun:test";
import fs from "fs/promises";
import { downloadCommentImages } from "../src/github/utils/image-downloader";
import type { CommentWithImages } from "../src/github/utils/image-downloader";
import type { Octokits } from "../src/github/api/client";

// Asset URLs and their signed download URLs share the asset's GUID.
const GUID_1 = "f871c23e-a84d-4f1f-b9a0-86626c63f161";
const GUID_2 = "0b0c9d33-4e6a-4f4e-8a1a-2f9e5c6d7e8f";
const GUID_3 = "a1b2c3d4-e5f6-4789-abcd-ef0123456789";

const assetUrl = (guid: string, suffix = "") =>
  `https://github.com/user-attachments/assets/${guid}${suffix}`;

const signedUrlFor = (guid: string, ext: string, token = "token") =>
  `https://private-user-images.githubusercontent.com/12345/98765432-${guid}${ext}?jwt=${token}`;

describe("downloadCommentImages", () => {
  let consoleLogSpy: any;
  let consoleWarnSpy: any;
  let consoleErrorSpy: any;
  let fsMkdirSpy: any;
  let fsWriteFileSpy: any;
  let fetchSpy: any;

  beforeEach(() => {
    // Spy on console methods
    consoleLogSpy = spyOn(console, "log").mockImplementation(() => {});
    consoleWarnSpy = spyOn(console, "warn").mockImplementation(() => {});
    consoleErrorSpy = spyOn(console, "error").mockImplementation(() => {});

    // Spy on fs methods
    fsMkdirSpy = spyOn(fs, "mkdir").mockResolvedValue(undefined);
    fsWriteFileSpy = spyOn(fs, "writeFile").mockResolvedValue(undefined);

    // Set fake system time for consistent filenames
    setSystemTime(new Date("2024-01-01T00:00:00.000Z")); // 1704067200000
  });

  afterEach(() => {
    consoleLogSpy.mockRestore();
    consoleWarnSpy.mockRestore();
    consoleErrorSpy.mockRestore();
    fsMkdirSpy.mockRestore();
    fsWriteFileSpy.mockRestore();
    if (fetchSpy) fetchSpy.mockRestore();
    setSystemTime(); // Reset to real time
  });

  const createMockOctokit = (): Octokits => {
    return {
      rest: {
        issues: {
          getComment: jest.fn(),
          get: jest.fn(),
        },
        pulls: {
          getReviewComment: jest.fn(),
          getReview: jest.fn(),
          get: jest.fn(),
        },
      },
    } as any as Octokits;
  };

  test("should create download directory", async () => {
    const mockOctokit = createMockOctokit();
    const comments: CommentWithImages[] = [];

    await downloadCommentImages(mockOctokit, "owner", "repo", comments);

    expect(fsMkdirSpy).toHaveBeenCalledWith("/tmp/github-images", {
      recursive: true,
    });
  });

  test("should handle comments without images", async () => {
    const mockOctokit = createMockOctokit();
    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "123",
        body: "This is a comment without images",
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(result.size).toBe(0);
    expect(consoleLogSpy).not.toHaveBeenCalledWith(
      expect.stringContaining("Found"),
    );
  });

  test("should detect and download images from issue comments", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // Mock octokit response
    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    // Mock fetch for image download
    const mockArrayBuffer = new ArrayBuffer(8);
    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => mockArrayBuffer,
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "123",
        body: `Here's an image: ![test](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(mockOctokit.rest.issues.getComment).toHaveBeenCalledWith({
      owner: "owner",
      repo: "repo",
      comment_id: 123,
      mediaType: { format: "full+json" },
    });

    expect(fetchSpy).toHaveBeenCalledWith(signedUrl);
    expect(fsWriteFileSpy).toHaveBeenCalledWith(
      "/tmp/github-images/image-1704067200000-0.png",
      Buffer.from(mockArrayBuffer),
    );

    expect(result.size).toBe(1);
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 1 image(s) in issue_comment 123",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(`Downloading ${imageUrl}...`);
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "✓ Saved: /tmp/github-images/image-1704067200000-0.png",
    );
  });

  test("should save a JPEG from an extensionless URL with a .jpg extension", async () => {
    // Regression for the case where a JPEG screenshot is pasted into an issue.
    // GitHub serves it from /user-attachments/assets/<uuid> (no extension), so
    // the URL-based guess used to default to ".png" while the bytes are JPEG —
    // producing a mislabeled file that the Anthropic API rejected with a 400.
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".jpg");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.get = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    // JPEG magic bytes: FF D8 FF, then arbitrary padding.
    const jpegBytes = new Uint8Array([0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10]);
    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => jpegBytes.buffer,
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_body",
        issueNumber: "143",
        body: `![Screenshot_20260607_204205_Chrome.jpg](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fsWriteFileSpy).toHaveBeenCalledWith(
      "/tmp/github-images/image-1704067200000-0.jpg",
      Buffer.from(jpegBytes.buffer),
    );
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.jpg",
    );
  });

  test("should handle review comments", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1, ".jpg");
    const signedUrl = signedUrlFor(GUID_1, ".jpg");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.pulls.getReviewComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "review_comment",
        id: "456",
        body: `Review comment with image: ![review](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(mockOctokit.rest.pulls.getReviewComment).toHaveBeenCalledWith({
      owner: "owner",
      repo: "repo",
      comment_id: 456,
      mediaType: { format: "full+json" },
    });

    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.jpg",
    );
  });

  test("should handle review bodies", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.pulls.getReview = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "review_body",
        id: "789",
        pullNumber: "100",
        body: `Review body: ![body](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(mockOctokit.rest.pulls.getReview).toHaveBeenCalledWith({
      owner: "owner",
      repo: "repo",
      pull_number: 100,
      review_id: 789,
      mediaType: { format: "full+json" },
    });

    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
  });

  test("should handle issue bodies", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1, ".gif");
    const signedUrl = signedUrlFor(GUID_1, ".gif");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.get = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_body",
        issueNumber: "200",
        body: `Issue description: ![issue](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(mockOctokit.rest.issues.get).toHaveBeenCalledWith({
      owner: "owner",
      repo: "repo",
      issue_number: 200,
      mediaType: { format: "full+json" },
    });

    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.gif",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 1 image(s) in issue_body 200",
    );
  });

  test("should handle PR bodies", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1, ".webp");
    const signedUrl = signedUrlFor(GUID_1, ".webp");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.pulls.get = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "pr_body",
        pullNumber: "300",
        body: `PR description: ![pr](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(mockOctokit.rest.pulls.get).toHaveBeenCalledWith({
      owner: "owner",
      repo: "repo",
      pull_number: 300,
      mediaType: { format: "full+json" },
    });

    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.webp",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 1 image(s) in pr_body 300",
    );
  });

  test("should handle multiple images in a single comment", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl1 = assetUrl(GUID_1);
    const imageUrl2 = assetUrl(GUID_2, ".jpg");
    const signedUrl1 = signedUrlFor(GUID_1, ".png", "token1");
    const signedUrl2 = signedUrlFor(GUID_2, ".jpg", "token2");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl1}"><img src="${signedUrl2}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "999",
        body: `Two images: ![img1](${imageUrl1}) and ![img2](${imageUrl2})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(2);
    expect(result.size).toBe(2);
    expect(result.get(imageUrl1)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(result.get(imageUrl2)).toBe(
      "/tmp/github-images/image-1704067200000-1.jpg",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 2 image(s) in issue_comment 999",
    );
  });

  test("should pair images by asset identifier even when the HTML order differs", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl1 = assetUrl(GUID_1);
    const imageUrl2 = assetUrl(GUID_2);
    const signedUrl1 = signedUrlFor(GUID_1, ".png", "token1");
    const signedUrl2 = signedUrlFor(GUID_2, ".png", "token2");

    // The rendered HTML lists the second asset first.
    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl2}"><img src="${signedUrl1}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "999",
        body: `Two images: ![img1](${imageUrl1}) and ![img2](${imageUrl2})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(2);
    expect(fetchSpy).toHaveBeenNthCalledWith(1, signedUrl1);
    expect(fetchSpy).toHaveBeenNthCalledWith(2, signedUrl2);
    expect(result.get(imageUrl1)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(result.get(imageUrl2)).toBe(
      "/tmp/github-images/image-1704067200000-1.png",
    );
  });

  test("should match asset identifiers case-insensitively", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1.toUpperCase());
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "1002",
        body: `Uppercase: ![test](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledWith(signedUrl);
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
  });

  test("should skip an image whose signed URL refers to a different asset", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    // The rendered HTML only contains a signed URL for a different asset.
    const signedUrl = signedUrlFor(GUID_2, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "1003",
        body: `Original image: ![test](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).not.toHaveBeenCalled();
    expect(result.size).toBe(0);
    expect(consoleWarnSpy).toHaveBeenCalledWith(
      `No matching signed URL found for ${imageUrl}, skipping`,
    );
  });

  test("should not pair a signed URL that only names the asset in a leading path segment", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    // The path segment mentions the requested asset, but the URL resolves to a
    // different asset's filename once ".." is applied.
    const signedUrl = `https://private-user-images.githubusercontent.com/${GUID_1}/../12345/98765432-${GUID_2}.png?jwt=token`;

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<a href="${signedUrl}">${signedUrl}</a>`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "1005",
        body: `Original image: ![test](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).not.toHaveBeenCalled();
    expect(result.size).toBe(0);
    expect(consoleWarnSpy).toHaveBeenCalledWith(
      `No matching signed URL found for ${imageUrl}, skipping`,
    );
  });

  test("should skip an image URL without an asset identifier", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl =
      "https://github.com/user-attachments/assets/test-image.png";
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "1004",
        body: `No identifier: ![test](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).not.toHaveBeenCalled();
    expect(result.size).toBe(0);
    expect(consoleWarnSpy).toHaveBeenCalledWith(
      `No matching signed URL found for ${imageUrl}, skipping`,
    );
  });

  test("should skip already downloaded images", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "111",
        body: `First: ![dup](${imageUrl})`,
      },
      {
        type: "issue_comment",
        id: "222",
        body: `Second: ![dup](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(1); // Only downloaded once
    expect(result.size).toBe(1);
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
  });

  test("should handle missing HTML body", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: null,
      },
    });

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "333",
        body: `Missing HTML: ![missing](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(result.size).toBe(0);
    expect(consoleWarnSpy).toHaveBeenCalledWith(
      "No HTML body found for issue_comment 333",
    );
  });

  test("should handle fetch errors", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: false,
      status: 404,
      statusText: "Not Found",
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "444",
        body: `Error image: ![error](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(result.size).toBe(0);
    expect(consoleErrorSpy).toHaveBeenCalledWith(
      `✗ Failed to download ${imageUrl}:`,
      expect.any(Error),
    );
  });

  test("should handle API errors gracefully", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest
      .fn()
      .mockRejectedValue(new Error("API rate limit exceeded"));

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "555",
        body: `API error: ![api-error](${imageUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(result.size).toBe(0);
    expect(consoleErrorSpy).toHaveBeenCalledWith(
      "Failed to process images for issue_comment 555:",
      expect.any(Error),
    );
  });

  test("should extract correct file extensions", async () => {
    const mockOctokit = createMockOctokit();
    const extensions = [
      { url: assetUrl(GUID_1, ".png"), ext: ".png" },
      { url: assetUrl(GUID_1, ".jpg"), ext: ".jpg" },
      { url: assetUrl(GUID_1, ".jpeg"), ext: ".jpeg" },
      { url: assetUrl(GUID_1, ".gif"), ext: ".gif" },
      { url: assetUrl(GUID_1, ".webp"), ext: ".webp" },
      { url: assetUrl(GUID_1, ".svg"), ext: ".svg" },
      // default
      { url: assetUrl(GUID_1), ext: ".png" },
    ];

    let callIndex = 0;
    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrlFor(GUID_1, "")}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    for (const { url, ext } of extensions) {
      const comments: CommentWithImages[] = [
        {
          type: "issue_comment",
          id: `${1000 + callIndex}`,
          body: `Test: ![test](${url})`,
        },
      ];

      setSystemTime(new Date(1704067200000 + callIndex));
      const result = await downloadCommentImages(
        mockOctokit,
        "owner",
        "repo",
        comments,
      );
      expect(result.get(url)).toBe(
        `/tmp/github-images/image-${1704067200000 + callIndex}-0${ext}`,
      );

      // Reset for next iteration
      fsWriteFileSpy.mockClear();
      callIndex++;
    }
  });

  test("should handle a signed URL missing for one of several images", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl1 = assetUrl(GUID_1);
    const imageUrl2 = assetUrl(GUID_2);
    const signedUrl1 = signedUrlFor(GUID_1, ".png");

    // Only one signed URL for two images
    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl1}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "666",
        body: `Two images: ![img1](${imageUrl1}) ![img2](${imageUrl2})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(1);
    expect(result.size).toBe(1);
    expect(result.get(imageUrl1)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(result.get(imageUrl2)).toBeUndefined();
    expect(consoleWarnSpy).toHaveBeenCalledWith(
      `No matching signed URL found for ${imageUrl2}, skipping`,
    );
  });

  test("should detect and download images from HTML img tags", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // Mock octokit response
    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    // Mock fetch for image download
    const mockArrayBuffer = new ArrayBuffer(8);
    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => mockArrayBuffer,
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "777",
        body: `Here's an HTML image: <img src="${imageUrl}" alt="test">`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(mockOctokit.rest.issues.getComment).toHaveBeenCalledWith({
      owner: "owner",
      repo: "repo",
      comment_id: 777,
      mediaType: { format: "full+json" },
    });

    expect(fetchSpy).toHaveBeenCalledWith(signedUrl);
    expect(fsWriteFileSpy).toHaveBeenCalledWith(
      "/tmp/github-images/image-1704067200000-0.png",
      Buffer.from(mockArrayBuffer),
    );

    expect(result.size).toBe(1);
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 1 image(s) in issue_comment 777",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(`Downloading ${imageUrl}...`);
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "✓ Saved: /tmp/github-images/image-1704067200000-0.png",
    );
  });

  test("should handle HTML img tags with different quote styles", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl1 = assetUrl(GUID_1, ".jpg");
    const imageUrl2 = assetUrl(GUID_2, ".png");
    const signedUrl1 = signedUrlFor(GUID_1, ".jpg", "token1");
    const signedUrl2 = signedUrlFor(GUID_2, ".png", "token2");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl1}"><img src="${signedUrl2}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "888",
        body: `Single quote: <img src='${imageUrl1}' alt="test"> and double quote: <img src="${imageUrl2}" alt="test">`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(2);
    expect(result.size).toBe(2);
    expect(result.get(imageUrl1)).toBe(
      "/tmp/github-images/image-1704067200000-0.jpg",
    );
    expect(result.get(imageUrl2)).toBe(
      "/tmp/github-images/image-1704067200000-1.png",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 2 image(s) in issue_comment 888",
    );
  });

  test("should handle mixed Markdown and HTML images", async () => {
    const mockOctokit = createMockOctokit();
    const markdownUrl = assetUrl(GUID_1);
    const htmlUrl = assetUrl(GUID_2, ".jpg");
    const signedUrl1 = signedUrlFor(GUID_1, ".png", "token1");
    const signedUrl2 = signedUrlFor(GUID_2, ".jpg", "token2");

    // The rendered HTML has the images in document order (HTML tag first),
    // which is the reverse of the order in which the URLs are extracted.
    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl2}"><img src="${signedUrl1}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "999",
        body: `HTML: <img src="${htmlUrl}" alt="test"> and Markdown: ![test](${markdownUrl})`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(2);
    expect(result.size).toBe(2);
    expect(result.get(markdownUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(result.get(htmlUrl)).toBe(
      "/tmp/github-images/image-1704067200000-1.jpg",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 2 image(s) in issue_comment 999",
    );
  });

  test("should deduplicate identical URLs from Markdown and HTML", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_1);
    const signedUrl = signedUrlFor(GUID_1, ".png");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "1000",
        body: `Same image twice: ![test](${imageUrl}) and <img src="${imageUrl}" alt="test">`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(1); // Only downloaded once
    expect(result.size).toBe(1);
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.png",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 1 image(s) in issue_comment 1000",
    );
  });

  test("should handle HTML img tags with additional attributes", async () => {
    const mockOctokit = createMockOctokit();
    const imageUrl = assetUrl(GUID_3, ".webp");
    const signedUrl = signedUrlFor(GUID_3, ".webp");

    // @ts-expect-error Mock implementation doesn't match full type signature
    mockOctokit.rest.issues.getComment = jest.fn().mockResolvedValue({
      data: {
        body_html: `<img src="${signedUrl}">`,
      },
    });

    fetchSpy = spyOn(global, "fetch").mockResolvedValue({
      ok: true,
      arrayBuffer: async () => new ArrayBuffer(8),
    } as Response);

    const comments: CommentWithImages[] = [
      {
        type: "issue_comment",
        id: "1001",
        body: `Complex tag: <img class="image" src="${imageUrl}" alt="test image" width="100" height="200">`,
      },
    ];

    const result = await downloadCommentImages(
      mockOctokit,
      "owner",
      "repo",
      comments,
    );

    expect(fetchSpy).toHaveBeenCalledTimes(1);
    expect(result.size).toBe(1);
    expect(result.get(imageUrl)).toBe(
      "/tmp/github-images/image-1704067200000-0.webp",
    );
    expect(consoleLogSpy).toHaveBeenCalledWith(
      "Found 1 image(s) in issue_comment 1001",
    );
  });
});