reverse-engineering-anything/tests/boundary/mcp/packetCaptureAvailability.test.ts

import { chmod, mkdir, writeFile } from "node:fs/promises";
import { join } from "node:path";

import { Client, InMemoryTransport } from "@modelcontextprotocol/client";
import { expect, it } from "vitest";
import { z } from "zod";

import {
  expandToolAvailability,
  sessionProvider,
} from "../../../src/contracts/toolOutputSchemaPrimitives.js";
import { createServer } from "../../../src/server/createServer.js";
import { createTestBinarySession } from "../../fixtures/binarySession.js";
import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";

// The server enables default packet tools only on Linux, where they can run.
const linux = process.platform === "linux";

const packetCaptureAvailability = async (
  environment: Readonly<Record<string, string | undefined>>,
): Promise<Record<string, unknown> | undefined> => {
  const session = createTestBinarySession(() => {
    throw new Error("binary analysis must not start during status discovery");
  });
  const server = createServer(
    { kind: "session", session },
    { environment: { ...environment, REA_MCP_OUTPUT_SCHEMA_PROFILE: "off" } },
  );
  const client = new Client({
    name: "packet-capture-availability",
    version: "1",
  });
  const [clientTransport, serverTransport] =
    InMemoryTransport.createLinkedPair();
  await server.connect(serverTransport);
  await client.connect(clientTransport);
  try {
    const response = await client.callTool({
      name: "binary_session",
      arguments: {},
    });
    if (response.isError === true) throw new Error("binary_session failed");
    const parsed = z
      .object({ result: sessionProvider })
      .parse(response.structuredContent).result;
    return expandToolAvailability(parsed.tool_availability).find(
      ({ name }) => name === "inspect_packet_capture",
    );
  } finally {
    await Promise.allSettled([client.close(), server.close(), session.close()]);
  }
};

const executableTshark = async (prefix: string): Promise<string> => {
  const directory = await createTestTempDirectory(prefix);
  await mkdir(join(directory, "bin"));
  const tshark = join(directory, "bin", "tshark");
  await writeFile(tshark, "");
  await chmod(tshark, 0o700);
  return join(directory, "bin");
};

it.runIf(linux)(
  "reports packet tools available for a PATH-only TShark install",
  async () => {
    const bin = await executableTshark("rea-packet-path-only-");
    expect(await packetCaptureAvailability({ PATH: bin })).toMatchObject({
      available: true,
      reason: "available",
    });
  },
);

it.runIf(linux)(
  "reports packet tools available for an absolute REA_TSHARK_COMMAND",
  async () => {
    const bin = await executableTshark("rea-packet-absolute-");
    expect(
      await packetCaptureAvailability({
        PATH: "",
        REA_TSHARK_COMMAND: join(bin, "tshark"),
      }),
    ).toMatchObject({ available: true, reason: "available" });
  },
);

it.runIf(linux)(
  "reports packet tools missing for a relative REA_TSHARK_COMMAND even when PATH holds TShark",
  async () => {
    const bin = await executableTshark("rea-packet-relative-");
    expect(
      await packetCaptureAvailability({
        PATH: bin,
        REA_TSHARK_COMMAND: "bin/tshark",
      }),
    ).toMatchObject({ available: false, reason: "provider_missing" });
  },
);

it("reports packet tools unavailable when no absolute PATH entry holds TShark", async () => {
  // Off Linux the host, not the missing tool, keeps packet tools unavailable.
  expect(
    await packetCaptureAvailability({ PATH: "relative-entry" }),
  ).toMatchObject({
    available: false,
    reason: linux ? "provider_missing" : "unsupported_host",
  });
});