cc-libs/tools/mcp-bridge/test/probe-computers.test.ts

import assert from "node:assert/strict";
import test from "node:test";
import { WebSocket } from "ws";
import { LinkRegistry } from "../src/link-server.js";
import { handleMcpRequest } from "../src/mcp-server.js";

test("probe-computers returns no computers message when registry is empty", async () => {
  const registry = new LinkRegistry();
  assert.equal(await registry.probeComputers(10), "No computers connected.");
});

test("probe-computers aggregates multiple successful responses", async () => {
  const registry = new LinkRegistry();
  const computer1 = new FakeSocket();
  const computer2 = new FakeSocket();

  registry.register({ computerId: 12, label: "base-turtle", ws: computer1 as unknown as WebSocket, connectedAt: 1, lastSeenAt: 1 });
  registry.register({ computerId: 13, label: "miner-1", ws: computer2 as unknown as WebSocket, connectedAt: 1, lastSeenAt: 1 });

  const promise = registry.probeComputers(50);
  computer1.respond(registry, 12, "pong from 12 (Label: base-turtle)");
  computer2.respond(registry, 13, "pong from 13 (Label: miner-1)");

  assert.equal(await promise, "pong from 12 (Label: base-turtle)\npong from 13 (Label: miner-1)");
});

test("probe-computers reports timeout for a connected computer that does not answer", async () => {
  const registry = new LinkRegistry();
  registry.register({ computerId: 14, label: "farm-turtle", ws: new FakeSocket() as unknown as WebSocket, connectedAt: 1, lastSeenAt: 1 });

  assert.equal(await registry.probeComputers(5), "timeout from 14 (Label: farm-turtle)");
});

test("MCP tool call returns text content", async () => {
  const registry = new LinkRegistry();
  const response = await handleMcpRequest(
    { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "probe-computers", arguments: {} } },
    registry,
    10,
  );

  assert.deepEqual(response, {
    jsonrpc: "2.0",
    id: 1,
    result: { content: [{ type: "text", text: "No computers connected." }] },
  });
});

test("MCP tools/list includes exec-lua schema", async () => {
  const registry = new LinkRegistry();
  const response = await handleMcpRequest({ jsonrpc: "2.0", id: 1, method: "tools/list" }, registry, 10);

  assert.deepEqual(response, {
    jsonrpc: "2.0",
    id: 1,
    result: {
      tools: [
        {
          name: "probe-computers",
          description: "Probe all linked ComputerCraft computers.",
          inputSchema: { type: "object", properties: {}, additionalProperties: false },
        },
        {
          name: "exec-lua",
          description: "Execute Lua code on a linked ComputerCraft computer.",
          inputSchema: {
            type: "object",
            properties: {
              computerId: { type: "number", description: "ComputerCraft computer id to execute on." },
              code: { type: "string", description: "Lua source code to execute." },
              timeoutMs: { type: "number", description: "Optional host-side timeout in milliseconds, max 30000." },
            },
            required: ["computerId", "code"],
            additionalProperties: false,
          },
        },
      ],
    },
  });
});

test("exec-lua sends code to the selected computer", async () => {
  const registry = new LinkRegistry();
  const computer = new FakeSocket();
  registry.register({ computerId: 12, label: "base-turtle", ws: computer as unknown as WebSocket, connectedAt: 1, lastSeenAt: 1 });

  const promise = registry.execLua(12, "print('hi') return 2 + 3", 50);
  assert.deepEqual(computer.lastRequest(), {
    type: "request",
    id: computer.lastRequest().id,
    method: "exec-lua",
    params: { code: "print('hi') return 2 + 3" },
  });

  computer.respond(registry, 12, { returns: [{ type: "number", value: 5 }], output: "hi\n" });
  assert.equal(
    await promise,
    'computer: 12 (Label: base-turtle)\nok: true\nreturns: [{"type":"number","value":5}]\noutput:\nhi',
  );
});

test("exec-lua reports unknown computer", async () => {
  const registry = new LinkRegistry();

  assert.equal(await registry.execLua(99, "return 1", 50), "No computer with id 99 connected.");
});

test("exec-lua formats computer error responses", async () => {
  const registry = new LinkRegistry();
  const computer = new FakeSocket();
  registry.register({ computerId: 12, label: "base-turtle", ws: computer as unknown as WebSocket, connectedAt: 1, lastSeenAt: 1 });

  const promise = registry.execLua(12, "print('before'); error('boom')", 50);
  computer.respondError(registry, 12, "boom", { output: "before\n" });

  assert.equal(await promise, "computer: 12 (Label: base-turtle)\nok: false\nerror: boom\noutput:\nbefore");
});

test("exec-lua reports timeouts", async () => {
  const registry = new LinkRegistry();
  registry.register({ computerId: 12, label: "base-turtle", ws: new FakeSocket() as unknown as WebSocket, connectedAt: 1, lastSeenAt: 1 });

  assert.equal(await registry.execLua(12, "while true do end", 5), "computer: 12 (Label: base-turtle)\nok: false\nerror: timeout");
});

test("MCP exec-lua validates required arguments", async () => {
  const registry = new LinkRegistry();
  const response = await handleMcpRequest(
    { jsonrpc: "2.0", id: 2, method: "tools/call", params: { name: "exec-lua", arguments: { computerId: 1 } } },
    registry,
    10,
  );

  assert.deepEqual(response, {
    jsonrpc: "2.0",
    id: 2,
    error: { code: -32602, message: "code must be a non-empty string" },
  });
});

test("MCP exec-lua validates timeoutMs", async () => {
  const registry = new LinkRegistry();
  const response = await handleMcpRequest(
    { jsonrpc: "2.0", id: 2, method: "tools/call", params: { name: "exec-lua", arguments: { computerId: 1, code: "return 1", timeoutMs: 0 } } },
    registry,
    10,
  );

  assert.deepEqual(response, {
    jsonrpc: "2.0",
    id: 2,
    error: { code: -32602, message: "timeoutMs must be a positive finite number" },
  });
});

class FakeSocket {
  sent: unknown[] = [];

  send(data: unknown): void {
    this.sent.push(data);
  }

  close(): void {
    return;
  }

  lastRequest(): { id: string; type: string; method: string; params?: unknown } {
    const last = this.sent.at(-1);
    assert.equal(typeof last, "string");
    return JSON.parse(last as string) as { id: string; type: string; method: string; params?: unknown };
  }

  respond(registry: LinkRegistry, computerId: number, result: unknown): void {
    const request = this.lastRequest();
    registry.handleFrame(this as unknown as WebSocket, JSON.stringify({ type: "response", id: request.id, ok: true, result }));

    assert.equal(computerId > 0, true);
  }

  respondError(registry: LinkRegistry, computerId: number, error: string, result: unknown): void {
    const request = this.lastRequest();
    registry.handleFrame(this as unknown as WebSocket, JSON.stringify({ type: "response", id: request.id, ok: false, error, result }));

    assert.equal(computerId > 0, true);
  }
}