Unable to connect to docker postgres container with pytest - postgresql

Question

I am trying to use pytest to run some simple integration test against postgresql db. I have to use python 2.7 so testcontainers are not the option.
my conftest.py looks like:
import pytest
import docker # this is a official system docker package
#pytest.fixture(scope="session")
def finalizer_function(container_id):
container_id.stop()
#pytest.fixture(scope="session", autouse=True)
def db_init():
"""
This db_init() method will start up docker container
which will be used throughout all the tests and once
all the tests are completed, containers will be
automatically removed.
:return:
"""
client = docker.from_env()
con_id = client.containers.run(
image="postgres:9.6",
name="postgres",
detach=True,
environment={
'POSTGRES_DB': 'postgres',
'POSTGRES_PASSWORD': 'test',
'POSTGRES_USER': 'postgres',
},
remove=True,
ports={"5432/tcp": 5432}
)
# yield con_id.stop()
and here is a very basic test I am not able to run test_postgres.py:
import docker
import socket
import psycopg2
from postgres import Postgres
def test_connection_to_db(db_init):
"""
:param db_init:
:return:
"""
print(socket.gethostname())
dbo = Postgres(
default_dbuser='postgres',
default_db='postgres',
host='127.0.0.1',
password='test',
port='5432'
)
_superuser = 'userx'
dbo.create_user(user=_superuser, password='start123', superuser=True)
consider that from postgres import Postgres is my custom postgres
module which works with no problem.
PYTHONPATH=lib pytest -s -vv tests/test_postgres.py
...
E OperationalError: server closed the connection unexpectedly
E This probably means the server terminated abnormally
E before or while processing the request.
However, when I start docker container by using fixture db_init
and I try to connect to this container with psql I can connect to db with no problem:
psql -h 127.0.0.1 -p 5432 -U postgres -d postgres
Password for user postgres:
psql (10.6, server 9.6.12)
Type "help" for help.
postgres=#
Please advise, Iam sure that there is just a silly mistake.
Thx