Testing question: is there a way to inject `fakeredis` ?

[gerazenobi]

Hi 👋

I was unit testing my functions that interact with Arq, however all the mocking is becoming rather heavy and I find there would be more value if I rather perform more of integration kind of testing; however I wouldn't want to depend on a real Redis and would like to use fakeredis instead: a common library to mock Redis.

I was previously using RQ and injecting FakeStrictRedis in it's setup was trivial, however I haven't found a way to do so with Arq and was wondering if it was possible or not at all.

RQ example

from redis import Redis
from rq import Queue
from rq import SimpleWorker

from app.config import (
    REDIS_DB,
    REDIS_HOST,
    REDIS_PASSWORD,
    REDIS_PORT,
    REDIS_SSL_ENABLED,
)


def start_worker():
    redis_connection = Redis(
        host=REDIS_HOST, port=REDIS_PORT, db=REDIS_DB, password=REDIS_PASSWORD, ssl=REDIS_SSL_ENABLED
    )
    queue = Queue(connection=redis_connection)

    worker = SimpleWorker(
        queues=[queue],
        connection=redis_connection,
    )
    worker.work()

in the above we would replace connection and queue with:

mock_redis_connection = FakeStrictRedis()
mock_queue = Queue("mock_queue", connection=mock_redis_connection)

I imagine the Arq counterpart would be something along the lines:

async def create_arq_client():
    return await create_pool( FakeStrictRedis() )

Thanks in advance.

[NiyazNz]

I was able to inject fakeredis this way:

from fakeredis import FakeServer
from fakeredis.aioredis import FakeConnection
from redis.asyncio.connection import ConnectionPool

@pytest.fixture
async def arq_redis():
    arq_redis = ArqRedis(
        connection_pool=ConnectionPool(
            server=FakeServer(),
            connection_class=FakeConnection,
        )
    )
    yield arq_redis
    await arq_redis.close(close_connection_pool=True)

It works, but requires removing the line with log_redis_info here https://github.com/samuelcolvin/arq/blob/9109c2e59d2b13fa59d246da03d19d7844a6fa19/arq/worker.py#L348

It uses INFO command which is not implemented in fakeredis

[eigenein]

log_redis_info() can be patched:

with patch("arq.worker.log_redis_info"):  # `fakeredis` does not support `INFO`
    try:
        yield worker
    finally:
        await worker.close()