Prove multi-db tests don't restrict access

example_settings.py

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+import os
+
+env = os.environ
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.postgresql_psycopg2",
+        "NAME": env.get("DB_NAME", default="example"),
+        "USER": env.get("DB_USER", default=""),
+        "PASSWORD": env.get("DB_PASSWORD", default=""),
+        "HOST": env.get("DB_HOST", default=""),
+        "PORT": env.get("DB_PORT", default=5432),
+        "TEST": {"NAME": env.get("DB_TEST_NAME", default="example-test")},
+    },
+    "secondary": {
+        "ENGINE": "django.db.backends.postgresql_psycopg2",
+        "NAME": env.get("DB2_NAME", default="secondary"),
+        "USER": env.get("DB2_USER", default=""),
+        "PASSWORD": env.get("DB2_PASSWORD", default=""),
+        "HOST": env.get("DB2_HOST", default=""),
+        "PORT": env.get("DB2_PORT", default=5432),
+        "TEST": {"NAME": env.get("DB2_TEST_NAME", default="example-secondary-test")},
+    },
+}

manage.py

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+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "example_settings")
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == "__main__":
+    main()

pyproject.toml

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+[tool.pytest.ini_options]
+DJANGO_SETTINGS_MODULE = "example_settings"
+python_files = ["test_example.py"]

requirements.txt

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+django==5.0.6
+psycopg==3.2.1
+pytest-django==4.8.0
+pytest==8.2.2
+uv==0.2.18

test_example.py

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+import pytest
+from django.db.transaction import atomic
+
+
+@pytest.mark.django_db(databases=["default"])
+def test_wrong_db():
+    with pytest.raises(RuntimeError, match="Database access not allowed"):
+        with atomic(using="secondary"):
+            pass