test(deploy): add tests for deploy-commands script

tests/deploy-commands.test.js

@@ -0,0 +1,55 @@
+jest.mock('discord.js', () => {
+  const original = jest.requireActual('discord.js');
+  const mockRest = {
+    put: jest.fn().mockResolvedValue([{ length: 1 }]),
+    setToken: jest.fn().mockReturnThis(),
+  };
+  return {
+    ...original,
+    REST: jest.fn(() => mockRest),
+    Routes: {
+      applicationCommands: jest.fn().mockReturnValue('/fake-route'),
+    },
+  };
+});
+
+jest.mock('fs', () => ({
+  readdirSync: jest.fn(() => ['ping.js']),
+}));
+jest.mock('node:path', () => {
+  const actual = jest.requireActual('node:path');
+  return {
+    ...actual,
+    join: (...args) => args.join('/'),
+    resolve: (...args) => args.join('/'),
+  };
+});
+
+describe('deploy-commands.js', () => {
+  let origEnv;
+  beforeAll(() => {
+    origEnv = { ...process.env };
+    process.env.CLIENT_ID = '12345';
+    process.env.DISCORD_TOKEN = 'token';
+  });
+
+  afterAll(() => {
+    process.env = origEnv;
+    jest.resetModules();
+  });
+
+  test('registers commands via REST API', async () => {
+    const mockLogger = { info: jest.fn(), warn: jest.fn(), error: jest.fn() };
+    jest.mock('../src/utils/logger', () => mockLogger);
+
+    // Run the script
+    await require('../deploy-commands.js');
+
+    const { REST } = require('discord.js');
+    expect(REST).toHaveBeenCalled();
+    const restInstance = REST.mock.results[0].value;
+    expect(restInstance.setToken).toHaveBeenCalledWith('token');
+    expect(restInstance.put).toHaveBeenCalledWith('/fake-route', { body: expect.any(Array) });
+    expect(mockLogger.info).toHaveBeenCalledWith(expect.stringContaining('Started refreshing'));
+  });
+});