A test case that hangs at GridOut.read:
import pymongo
from bson.binary import Binary
from gridfs import GridFS
client = pymongo.MongoClient()
db = client.test
gfs = GridFS(db)
files_id = gfs.put('foobar')
db.fs.chunks.update({'files_id': files_id}, {'$set': {'data': Binary('foo', 0)}})
out = gfs.get(files_id)
out.read()
The same problem occurs in GridOut.readline.
This problem was reported here: https://github.com/mongodb/mongo-python-driver/pull/271