prepareBot

Initialises a Bot for in-process testing.

Signature

async function prepareBot<TContext extends Context = Context, TApi extends Api = Api>(
  bot: Bot<TContext, TApi>,
  options?: PrepareOptions,
): Promise<PrepareBotReturn<TContext>>;

Parameters

Parameter	Type	Description
bot	Bot<TContext, TApi>	The grammY bot under test
options	PrepareOptions	Optional configuration

PrepareOptions

interface PrepareOptions {
  responses?: Responses;
  warnOnUnregisteredChats?: boolean;
}

Field	Type	Default	Description
responses	Responses	{}	Map of API method → canned response. Methods not listed resolve to true.
warnOnUnregisteredChats	boolean	true	Emits a console.warn when the bot sends to a chat not registered with Chats.

Return value

interface PrepareBotReturn<TContext extends Context = Context> {
  chats: Chats<TContext>;
}

What it does

1. Creates OutgoingRequests, IdleTracker, and Chats instances.
2. Builds default canned responses and merges in options.responses.
3. Installs the capture transformer on bot.api.
4. Pre-populates bot.botInfo with a generic fixture (skips getMe).
5. Awaits bot.init().
6. Wires the bot reference into the Chats orchestrator.

Example

import { prepareBot } from 'grammy-testing';
import { Bot } from 'grammy';

const bot = new Bot('token');
bot.command('start', (ctx) => ctx.reply('Hello!'));

const { chats } = await prepareBot(bot);
const user = chats.newUser();

await user.sendCommand('/start');
expect(user.replies.lastOrThrow().text).toBe('Hello!');

With responses

const { chats } = await prepareBot(bot, {
  responses: {
    getChatMember: { status: 'administrator', user: { id: 1, is_bot: false, first_name: 'Alice' } },
  },
});

See also

• prepareComposer — for testing a Composer in isolation
• prepareMiddleware — for testing a single middleware
• Response Mocking — full responses documentation