simcord 0.10.0

SimCord — discord.py testing framework. Simulate Discord, test your bot offline: no network, no token, no ToS.

SimCord

The discord.py testing framework — simulate Discord, test your bot offline.

Test your discord.py bot with a full virtual Discord environment: no network, no token, no test server, no Terms of Service concerns. SimCord is the missing testing library for discord.py bots.

Quickstart · Documentation · Parity matrix · Contributing

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SimCord is a discord.py testing framework that gives your bot a fake but faithful Discord to run against. Simulate users sending messages, invoking slash commands, clicking buttons and submitting modals — then assert on exactly what your bot did:

async def test_ping(simcord_env):
    channel = simcord_env.create_guild().create_text_channel("general")
    alice = simcord_env.guild.add_member(simcord_env.create_user("alice"))

    await alice.send(channel, "!ping")          # full gateway round trip

    assert channel.last_message.content == "Pong!"

⚠️ Alpha. The core surface (messages, prefix commands, slash commands, components, modals, permissions, reactions, threads, DMs, time control) works; see the parity matrix for the long tail. Unimplemented routes always fail loudly — SimCord never silently fakes success.

Why SimCord?

Unit tests cover your business logic, but the bugs that bite Discord bots live in the glue: converters, checks, permissions, forgotten tree.sync() calls, double-acknowledged interactions, oversized embeds. Until now the only way to test that layer was manually, in a real server. SimCord runs all of discord.py's real machinery — its parsers, cache, command frameworks and views — against a faithful mock of Discord's REST API and gateway, entirely in-process.

🎯 Real discord.py semantics	Server-side permission checks with authentic error codes (50013 Missing Permissions…), interaction lifecycle rules (40060 on double-ack), role hierarchy, timeouts, ephemeral visibility, validation limits.
🐛 Real bugs caught	Invoking a never-synced slash command fails your test, just like production. Clicking a disabled button is impossible, just like the client. Unhandled bot errors fail the test by default.
⚡ Fast & deterministic	No sleeps, no network, reproducible IDs and timestamps. The framework tracks the bot's tasks and settles after every action.
⏩ Time control	env.advance_time(180) fires view timeouts and resets cooldowns instantly — no real waiting.
🔍 Debuggable failures	Failing tests automatically include a transcript of every gateway event and REST call — exactly what your bot did, in order.
📢 Loud gaps	Anything not implemented raises RouteNotImplemented naming the route. Never silent fake success.

Install

pip install simcord[pytest]

Requires Python 3.11+ and discord.py 2.7+. Zero dependencies beyond discord.py itself.

Quickstart

Tell the bundled pytest plugin how to build your bot:

# conftest.py
import pytest
from mybot import create_bot   # however your project builds its commands.Bot

@pytest.fixture
def simcord_bot():
    return create_bot()

Then write tests against the simcord_env fixture:

import discord

async def test_ban_slash_command(simcord_env):
    guild = simcord_env.create_guild()
    channel = guild.create_text_channel("mod")
    mods = guild.create_role("Mods", permissions=discord.Permissions(ban_members=True))
    mod = guild.add_member(simcord_env.create_user("mod"), roles=[mods])
    target = guild.add_member(simcord_env.create_user("spammer"))

    result = await mod.slash(channel, "ban", user=target, reason="spam")

    assert result.ephemeral
    assert result.response.content == f"Banned {target.mention}: spam"
    assert guild.get_ban(target) is not None

async def test_offer_expires(simcord_env):
    channel = simcord_env.create_guild().create_text_channel("general")
    alice = simcord_env.guild.add_member(simcord_env.create_user("alice"))

    result = await alice.slash(channel, "offer")    # bot replies with a View(timeout=180)
    await simcord_env.advance_time(180)             # instant — the view times out

    assert "expired" in channel.last_message.content

Buttons, selects, modals, context menus, autocomplete, reactions, threads, DMs, fault injection and more: see the documentation. Prefer explicit control? async with simcord.run(bot) as env: works in any async test framework.

How it works

discord.py has two narrow seams: every REST call funnels through HTTPClient.request, and every gateway event enters through ConnectionState.parsers. SimCord replaces the first with a fake routed to an in-memory backend (a single source of truth for guilds, channels, members, messages, commands and interactions) and injects Discord-shaped payloads through the second. Everything between those seams — which is everything your bot touches — is real discord.py code running unmodified.

test ──► builders/actors ──► virtual backend (single source of truth)
                                   │                     │
                  gateway payloads ▼                     ▼ REST responses
                  ConnectionState.parsers        FakeHTTPClient route table
                                   │                     ▲
                                   ▼                     │
                                  your real, unmodified bot

Details in the architecture docs.

discord.py testing — common use cases

SimCord covers the full range of discord.py bot testing scenarios:

• discord.py unit testing — test individual commands in isolation
• discord.py integration testing — test full command flows with permissions, roles and channels
• discord.py mock events — fire any gateway event (member join, reaction add, voice state…) without a real server
• discord.py mock Discord — a full in-memory Discord server your bot can't tell from the real thing
• discord.py command testing — prefix commands, slash commands, context menus, autocomplete
• discord.py interaction testing — buttons, selects, modals, ephemeral responses, deferred replies
• discord.py bot testing without a token — no .env, no test guild, no rate limits

Comparison

	SimCord	dpytest	Manual test server
No network / no token	✅	✅	❌
Real discord.py internals	✅	Partial	✅
Slash commands & components	✅	❌	✅
Authentic error codes	✅	❌	✅
Time control	✅	❌	❌
Failure transcripts	✅	❌	❌
Maintained for discord.py 2.x	✅	❌	—

Contributing

See CONTRIBUTING.md. Bug reports with a failing test are gold; if your bot hits an unimplemented route, the error names it — please open a parity gap issue.

License

MIT. Unofficial — not affiliated with Discord Inc. or the discord.py project.