lam-agent-vicinae/src/__tests__/snip.test.ts

import { access, mkdir, rm, utimes, writeFile } from "node:fs/promises";
import { afterEach, beforeEach, describe, expect, it } from "vitest";
import { listSnipFiles, readSnipContext, removeSnipFiles, snipDirectory } from "../lib/snip";

/**
 * The snip handoff crosses a command boundary as a serialized launch context, so
 * every field arrives as unknown. This is the boundary where a wrong type would
 * otherwise reach the file system as a path.
 */

describe("readSnipContext", () => {
  it("reads the fields the snip command writes", () => {
    expect(
      readSnipContext({
        snipPath: "/tmp/snip.png",
        snipError: "no tool",
        sessionId: "abc123",
      }),
    ).toEqual({ snipPath: "/tmp/snip.png", snipError: "no tool", sessionId: "abc123" });
  });

  it("returns nothing for a launch with no context at all", () => {
    expect(readSnipContext(undefined)).toEqual({});
    expect(readSnipContext(null)).toEqual({});
  });

  it("ignores a context that is not an object", () => {
    expect(readSnipContext("snip.png")).toEqual({});
    expect(readSnipContext(42)).toEqual({});
    expect(readSnipContext(["/tmp/snip.png"])).toEqual({});
  });

  it("drops a value that is not a string rather than passing it on", () => {
    // A number or object here would reach `readAttachment` as a path.
    expect(readSnipContext({ snipPath: 42, sessionId: { id: "x" } })).toEqual({});
  });

  it("treats an empty string as absent", () => {
    expect(readSnipContext({ snipPath: "", sessionId: "" })).toEqual({});
  });

  it("ignores unknown keys, so a stray field cannot widen the contract", () => {
    expect(readSnipContext({ snipPath: "/tmp/snip.png", somethingElse: "/etc/passwd" })).toEqual({
      snipPath: "/tmp/snip.png",
    });
  });

  it("reads a payload that only names a conversation, which is a cancelled snip", () => {
    expect(readSnipContext({ sessionId: "abc123" })).toEqual({ sessionId: "abc123" });
  });
});

describe("snipDirectory", () => {
  it("keeps snips under the extension's support directory, not a temp directory", () => {
    // A stored conversation holds the path, so it has to survive a reboot.
    expect(snipDirectory()).toBe("/tmp/lam-agent-support/snips");
  });
});

describe("listSnipFiles", () => {
  const DIRECTORY = "/tmp/lam-agent-support/snips";

  beforeEach(async () => {
    await rm(DIRECTORY, { recursive: true, force: true });
  });

  afterEach(async () => {
    await rm(DIRECTORY, { recursive: true, force: true });
  });

  it("returns nothing before anything has been snipped", async () => {
    await expect(listSnipFiles()).resolves.toEqual([]);
  });

  it("reports each capture with the time it was written", async () => {
    await mkdir(DIRECTORY, { recursive: true });
    const path = `${DIRECTORY}/one.png`;
    await writeFile(path, "png");
    const when = new Date(Date.now() - 60_000);
    await utimes(path, when, when);

    const [file] = await listSnipFiles();

    expect(file.path).toBe(path);
    expect(Date.now() - file.mtimeMs).toBeGreaterThan(30_000);
  });

  it("ignores a subdirectory, which is not a capture", async () => {
    await mkdir(`${DIRECTORY}/nested`, { recursive: true });

    await expect(listSnipFiles()).resolves.toEqual([]);
  });
});

describe("removeSnipFiles", () => {
  const DIRECTORY = "/tmp/lam-agent-support/snips";
  const OUTSIDE = "/tmp/lam-agent-not-a-snip.png";

  beforeEach(async () => {
    await rm(DIRECTORY, { recursive: true, force: true });
    await mkdir(DIRECTORY, { recursive: true });
    await writeFile(OUTSIDE, "do not delete me");
  });

  afterEach(async () => {
    await rm(DIRECTORY, { recursive: true, force: true });
    await rm(OUTSIDE, { force: true });
  });

  it("deletes a capture inside the snip directory and counts it", async () => {
    const path = `${DIRECTORY}/one.png`;
    await writeFile(path, "png");

    await expect(removeSnipFiles([path])).resolves.toBe(1);
    await expect(access(path)).rejects.toThrow();
  });

  it("counts a file that was already gone, because the question is whether it is still there", async () => {
    await expect(removeSnipFiles([`${DIRECTORY}/never-existed.png`])).resolves.toBe(1);
  });

  it("refuses a path outside the snip directory and does not count it", async () => {
    // These paths come out of stored JSON, which is data rather than code, so
    // this must not be a general-purpose delete-any-file helper.
    await expect(removeSnipFiles([OUTSIDE])).resolves.toBe(0);

    await expect(access(OUTSIDE)).resolves.toBeUndefined();
  });

  it("refuses a path that climbs out of the directory", async () => {
    await expect(removeSnipFiles([`${DIRECTORY}/../../lam-agent-not-a-snip.png`])).resolves.toBe(0);

    await expect(access(OUTSIDE)).resolves.toBeUndefined();
  });

  it("refuses the directory itself", async () => {
    await expect(removeSnipFiles([DIRECTORY])).resolves.toBe(0);

    await expect(access(DIRECTORY)).resolves.toBeUndefined();
  });

  it("keeps going when one path in the batch is refused, and counts only the one it acted on", async () => {
    const inside = `${DIRECTORY}/one.png`;
    await writeFile(inside, "png");

    await expect(removeSnipFiles([OUTSIDE, inside])).resolves.toBe(1);

    await expect(access(inside)).rejects.toThrow();
    await expect(access(OUTSIDE)).resolves.toBeUndefined();
  });
});