XREAD command returns empty list if count is bigger than number of messages

[sveta-afanaseva]

Describe the bug
Command XREAD returns empty list when COUNT is bigger than count of messages in stream. However, in redis python sdk it works another way (it returns all messages from the stream)

Some proofs
https://github.com/redis/redis-py/blob/emb-examples/doctests/dt_stream.py#L43
https://redis.io/docs/data-types/streams/

To Reproduce
Steps to reproduce the behavior:

1. Create FakeRedis object
2. Add message in stream with command xadd
3. Call xread command for your stream with argument count=100
4. Get empty list

Expected behavior
Expected list of all messages in stream

Desktop (please complete the following information):

• OS: Windows
• python version 3.10
• redis-py version 5.0.1

[cunla]

Hi, can you provide the test for it? to run against real redis and fakeredis?

[sveta-afanaseva]

Yes, try this

from fakeredis import FakeRedis
from redis import Redis

def test_redis():
    fake_redis = FakeRedis()
    real_redis = Redis(host="localhost", port=6379)
    
    fake_redis.xadd("test", {"x": 1})
    real_redis.xadd("test", {"x": 1})
    
    res1 = fake_redis.xread(streams={"test": "0"}, count=100, block=10)
    res2 = real_redis.xread(streams={"test": "0"}, count=100, block=10)
    assert len(res1) == len(res2)

[sveta-afanaseva]

Oh, sorry, it returns empty list, not None. My mistake

[cunla]

Ok, I wrote a test that is able to replicate it. I'll try to fix it this weekend.