Tests

Helpers

Block external requests in tests

When writing tests, it’s important to ensure they don’t accidentally make external network requests. This helps keep tests fast, reliable, and prevents unintended side effects. The toolbox provides two helpers to block external requests while allowing localhost connections.

Pytest Fixture: `block_external_requests`

For pytest-based tests, use the block_external_requests fixture. This fixture patches socket.getaddrinfo to only allow connections to localhost addresses (localhost, 127.0.0.1, ::1, 0.0.0.0).

If you want to apply it to all tests in your suite automatically, register the helper plugin and create a wrapper fixture in your conftest.py:

import pytest

pytest_plugins = [
    "ambient_toolbox.tests.fixtures.block_external_requests",
]


@pytest.fixture(autouse=True)
def block_external_requests_autouse(block_external_requests):
    """Auto-apply external request blocking to all tests."""
    pass

Allowing additional hosts: If you need to allow specific external hosts (e.g., a test API server), you can configure them via Django settings:

# In your Django settings or test settings
BLOCKING_EXTERNAL_REQUESTS_ALLOWED_HOSTS = [
    "api.test-server.com",
    "cdn.test-server.com",
    "192.168.1.100",  # IP addresses are also supported
]

The fixture will automatically detect and apply these settings if Django is available and configured. If Django is not available or not configured, it will simply use the default localhost addresses.

Django Test Runner: `BlockingExternalRequestsRunner`

For Django projects, you can use the custom test runner to block external requests across your entire test suite.

Add this to your Django settings:

TEST_RUNNER = "ambient_toolbox.tests.test_runners.block_external_requests.BlockingExternalRequestsRunner"

Then run your tests normally:

python manage.py test

The runner will automatically block all external network requests during test execution, allowing only localhost connections.

Allowing additional hosts: If you need to allow specific external hosts (e.g., a test API server), you can configure them via Django settings:

# In your Django settings or test settings
BLOCKING_EXTERNAL_REQUESTS_ALLOWED_HOSTS = [
    "api.test-server.com",
    "cdn.test-server.com",
    "192.168.1.100",  # IP addresses are also supported
]

The runner will merge these additional hosts with the default localhost addresses (localhost, 127.0.0.1, ::1, 0.0.0.0), so both default and custom hosts will be allowed during test execution.

Note: Both helpers raise an AssertionError when an external request is detected, with a message like: "External request to example.com detected". This makes it easy to identify which tests are making unwanted external calls.

Mixins

ClassBasedViewTestMixin

This test case mixin helps out when unit-testing a view. It provides methods for the three main ways to request a view: get, post and delete. Authentication and the creation of the request is handled internally.

class MyViewTestCase(ClassBasedViewTestMixin, TestCase):
    view_class = views.MyView

    def test_get_call_authenticated(self):
        response = self.get(user=self.user, url_params={'pk': 17})
        self.assertEqual(response.status_code, 200)

    def test_get_call_not_authenticated(self):
        response = self.get(user=None, url_params={'pk': 17})
        self.assertEqual(response.status_code, 403)

    def test_post_call(self):
        response = self.post(user=self.user, data={'foo': 'bar'}, url_params={'pk': 17})
        self.assertEqual(response.status_code, 200)

    def test_delete_call(self):
        response = self.delete(user=self.user, url_params={'pk': 17})
        self.assertEqual(response.status_code, 202)

RequestProviderMixin

In many cases, you will find yourself in the position that you need a request in your unittests. A wise programmer will try to avoid looping the request object through all services — but from time to time you end up with a well-written method which takes the request as a parameter.

For these cases, the toolbox provides a handy mixin, from which you can derive your test class. Then you will be able to use a method called get_request(user=None). If you specify a user, he/she will be the request user. In most cases you won’t need to set an explicit url, so / will be taken as a default. If you do need it, pass set the url parameter.

from django.test import TestCase
from ambient_toolbox.tests.mixins import RequestProviderMixin


class MyAwesomeTest(RequestProviderMixin, TestCase):

    def test_something_with_a_request_without_a_user(self):
        request = self.get_request(None)
        ...

    def test_something_with_a_request_having_a_user(self):
        ...
        request = self.get_request(user=my_user)
        ...

    def test_something_with_a_request_with_set_url(self):
        ...
        request = self.get_request(url='/path/to/something')
        ...

BaseViewPermissionTestMixin

Please refer to the view layer section to get details about how to use this view test mixin.

DjangoMessagingFrameworkTestMixin

If you’re working with Django views, you might want to use (and therefore test) the Django messaging framework. To make this as easy as possible, inherit your view test class from the DjangoMessagingFrameworkTestMixin.

You can either check for a full message or just for a partial one.

from django.test import TestCase
from ambient_toolbox.tests.mixins import DjangoMessagingFrameworkTestMixin


class MyViewTest(DjangoMessagingFrameworkTestMixin, TestCase):

    def test_my_message_full_case(self):
        # The view creates a message: "It's sunny on Sundays."
        view = function_to_instantiate_your_view()
        self.assert_full_message_in_request(
            view.request, "It's sunny on Sundays.")

    def test_my_message_partial_case(self):
        # The view creates a message: "I have added *n* new records" with "n" being a variable
        view = function_to_instantiate_your_view()
        self.assert_partial_message_in_request(
            view.request, 'I have added')

Test structure validator

Motivation

When working on a Django project, it can happen very easily that you create unit tests in a way that they won’t be auto-discovered. The mean thing about this is that you can still run those tests - so it’s hard to find those issues.

The most common mistakes are forgetting the __init__.py in the directory or not prefixing your python files with test_. In addition, it checks for files like test_*.py which don’t live inside a tests/ directory.

To tackle this problem, we created a handy management command you can run manually or integrate in your CI pipeline.

python manage.py validate_test_structure

Note: If you enforce 100% coverage in your project, this check is redundant, since the coverage will detect any tests / test files which are not executed.

Configuration

You can define all of those settings variables in your main Django settings file.

Variable	Type	Default	Explanation
TEST_STRUCTURE_VALIDATOR_FILE_WHITELIST	list	[]	Filenames which will be ignored, will always ignore `__init__`
TEST_STRUCTURE_VALIDATOR_BASE_DIR	Path	settings.BASE_DIR	Root path to your application (BASE_DIR in a vanilla Django setup)
TEST_STRUCTURE_VALIDATOR_BASE_APP_NAME	str	“apps”	Directory where all your Django apps live in, can be set to “”.
TEST_STRUCTURE_VALIDATOR_APP_LIST	list	settings.INSTALLED_APPS	List of all your Django apps you want to validate
TEST_STRUCTURE_VALIDATOR_IGNORED_DIRECTORY_LIST	list	[]	Directories which will be ignored, will always ignore `__pycache__`
TEST_STRUCTURE_VALIDATOR_MISPLACED_TEST_FILE_WHITELIST	list	[]	Test files which will be ignored even though they don’t live in `tests/`