import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
import type { EventEmitter } from "node:events";
const connectMock = vi.fn();
const listToolsMock = vi.fn(async () => ({ tools: [{ name: "sshExecute" }] }));
const callToolMock = vi.fn(async () => ({ content: [{ type: "text", text: "ok" }] }));
const closeMock = vi.fn();
const transportCloseMock = vi.fn();
const transportInstances: Array<{ options: unknown; stderr: EventEmitter }> = [];
vi.mock("@modelcontextprotocol/sdk/client/index.js", () => {
class MockClient {
listTools = listToolsMock;
callTool = callToolMock;
connect = connectMock;
close = closeMock;
}
return { Client: MockClient };
});
vi.mock("@modelcontextprotocol/sdk/client/stdio.js", async () => {
const { EventEmitter } = await import("node:events");
class MockTransport extends EventEmitter {
public stderr = new EventEmitter();
public options: unknown;
constructor(options: unknown) {
super();
this.options = options;
transportInstances.push({ options, stderr: this.stderr });
}
close = transportCloseMock;
}
return { StdioClientTransport: MockTransport };
});
describe("simulator CLI", () => {
const originalArgv = process.argv.slice();
const originalEnv = { ...process.env };
let consoleLogMock: ReturnType<typeof vi.spyOn>;
beforeEach(() => {
process.argv = originalArgv.slice(0, 2);
for (const key of Object.keys(process.env)) {
if (!(key in originalEnv)) {
delete process.env[key];
}
}
Object.assign(process.env, originalEnv);
transportInstances.length = 0;
connectMock.mockResolvedValue(undefined);
closeMock.mockResolvedValue(undefined);
transportCloseMock.mockResolvedValue(undefined);
listToolsMock.mockClear();
callToolMock.mockClear();
consoleLogMock = vi.spyOn(console, "log").mockImplementation(() => {});
});
afterEach(() => {
process.argv = originalArgv.slice();
for (const key of Object.keys(process.env)) {
if (!(key in originalEnv)) {
delete process.env[key];
}
}
Object.assign(process.env, originalEnv);
consoleLogMock.mockRestore();
connectMock.mockReset();
closeMock.mockReset();
transportCloseMock.mockReset();
});
it("lists available tools", async () => {
process.argv = ["node", "simulator", "list"];
const { main } = await import("../src/simulator.js");
await main();
expect(listToolsMock).toHaveBeenCalledTimes(1);
expect(consoleLogMock).toHaveBeenCalled();
});
it("invokes a tool with provided payload", async () => {
process.argv = ["node", "simulator", "call", "sshExecute", '{"profile":"training"}'];
const { main } = await import("../src/simulator.js");
await main();
expect(callToolMock).toHaveBeenCalledWith({ name: "sshExecute", arguments: { profile: "training" } });
expect(consoleLogMock).toHaveBeenCalled();
});
it("passes environment overrides to the transport", async () => {
process.env.MCP_SERVER_COMMAND = "custom-node";
process.env.MCP_SERVER_ARGS = "server.js, --flag";
process.env.MCP_SERVER_CWD = "/tmp";
process.argv = ["node", "simulator", "list"]; // shortlist run
const { main } = await import("../src/simulator.js");
await main();
expect(transportInstances).toHaveLength(1);
expect(transportInstances[0]?.options).toMatchObject({
command: "custom-node",
args: ["server.js", "--flag"],
cwd: "/tmp"
});
});
});
