如何在 django、pytest、postgres 中应用迁移

Question

How to auto-apply migrations to test database?

Error

django.db.utils.ProgrammingError: relation "users" does not exist
E               LINE 1: ...ers"."phone_confirmed", "users"."last_login" FROM "users" WH...

pytest.ini

[pytest]
DJANGO_SETTINGS_MODULE = ma_saas.settings
addopts = --migrations

database_fixture.py

import pytest
from django.db import connections

import psycopg2
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT

def run_sql(sql):
    conn = psycopg2.connect(database='postgres')
    conn.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
    cur = conn.cursor()
    cur.execute(sql)
    conn.close()

@pytest.yield_fixture(scope='session')
def django_db_setup():
    from django.conf import settings
    settings.DATABASES['default']['NAME'] = 'test_db'
    run_sql('DROP DATABASE IF EXISTS test_db')
    run_sql('CREATE DATABASE test_db')
    yield
    for connection in connections.all():
        connection.close()
    run_sql('DROP DATABASE test_db')

I think it is better to create a database and apply its migrations in the database_fixture better.

Answer 1

It was not so obvious. But we should use django_db_blocker to run commands.

from django.core.management import call_command

@pytest.yield_fixture(scope='session') # or @pytest.fixture(scope='session')
def django_db_setup(django_db_blocker):
    from django.conf import settings
    test_database_name = 'test_db'
    settings.DATABASES['default']['NAME'] = test_db

    run_sql(f'DROP DATABASE IF EXISTS {test_db}')
    run_sql(f'CREATE DATABASE {test_db}')
    with django_db_blocker.unblock():
        call_command('migrate', '--noinput')
    yield
    for connection in connections.all():
        connection.close()

    run_sql(f'DROP DATABASE {test_db}')