def test1(db):
    m = MyModel.objects.create()
    assert m.id == 1 # => true

def test2(db):
    m = MyModel.objects.create()
    assert m.id == 1 # true ONLY if I run the test alone.

import psycopg2
import pytest
from django.db import connections
from pytest_postgresql import factories


def create_postgis_ext(host, port, user, dbname, password):
    with (
        psycopg2.connect(
            dbname=dbname,
            user=user,
            password=password,
            host=host,
            port=port,
        ) as con,
        con.cursor() as con,
    ):
        con.execute("CREATE EXTENSION postgis;")



  postgres_options = (
      "-c wal_level=minimal "
      "-c max_wal_senders=0 "
      "-c fsync=off "
      "-c synchronous_commit=off "
      "-c full_page_writes=off "
      "-c checkpoint_timeout=1d "  # Long timeout to avoid checkpoints
      "-c max_wal_size=10GB "  # Large max WAL size to avoid forced checkpoints
      "-c shared_buffers=256MB "  # Increased shared buffers for better caching
      "-c work_mem=64MB"  # Larger work memory for faster operations
  )
  postgresql_proc_general = factories.postgresql_proc(postgres_options=postgres_options, dbname="general")
  postgresql_proc_gis = factories.postgresql_proc(
      postgres_options=postgres_options, load=[create_postgis_ext], dbname="gis"
  )
  postgresql_proc_othergis = factories.postgresql_proc(
      postgres_options=postgres_options, load=[create_postgis_ext], dbname="othergis"
  )

  @pytest.fixture(scope="session")
  def django_db_setup(request, postgresql_proc_general, postgresql_proc_gis, postgresql_proc_othergis):
      from django.conf import settings

      # remove cached_property of connections.settings from the cache
      del connections.__dict__["settings"]
      db_fixture_mapping = {
          "default": postgresql_proc_general,
          "gis": postgresql_proc_gis,
          "othergis": postgresql_proc_othergis,
      }
      for db, fixture in db_fixture_mapping.items():
          settings.DATABASES[db]["ENGINE"] = "django.contrib.gis.db.backends.postgis"
          settings.DATABASES[db]["NAME"] = fixture.dbname
          settings.DATABASES[db]["USER"] = fixture.user
          settings.DATABASES[db]["PASSWORD"] = fixture.password
          settings.DATABASES[db]["HOST"] = fixture.host
          settings.DATABASES[db]["PORT"] = fixture.port
          settings.DATABASES[db]["OPTIONS"] = {"connect_timeout": 10}
          settings.DATABASES[db]["TEST"]["NAME"] = fixture.dbname

      # re-configure the settings given the changed database config
      connections.settings = connections.configure_settings(settings.DATABASES)
      # open a connection to the database with the new database config
      connections["default"] = connections.create_connection("default")
      yield request.getfixturevalue("django_db_setup")