Django

Fast Tests

Speeding up the tests

Running tests in parallel

As long as your tests are properly isolated, you can run them in parallel to gain a speed up on multi-core hardware.

 

 

python mange.py --parallel

Speeding up the tests

Password hashing

The default password hasher is rather slow by design. If you’re authenticating many users in your tests, you may want to use a custom settings file and set the PASSWORD_HASHERS setting to a faster hashing algorithm:

 
PASSWORD_HASHERS = ['django.contrib.auth.hashers.MD5PasswordHasher',]

Speeding up the tests

Preserving the test database

 

The test --keepdb option preserves the test database between test runs. It skips the create and destroy actions which can greatly decrease the time to run tests.

Putting the settings to test

​manage.py test Ran 442 tests in 294.374s
manage.py test --parallel Ran 442 tests in 136.189s (2 cpus)
manage.py  test --parallel --keepdb Ran 442 tests in 138.454s
manage.py  test --parallel --keepdb
 +  with md5 password hashing		 Ran 442 tests in 130.763s
manage.py  test --parallel --keepdb + pg  without fsync Ran 442 tests in 82.288s

Other tips

  • Use logging instead of printing
  • -W ignore
  • ./manage.py test --reverse

 

Running only specific tests

python manage.py testmail.tests.test_send_notification.TestSendNotificationConditionHours

 

 

In Pycharm:

right click on test -> copy reference

 

 

Avoid running migrations

if env.bool("TEST_WITHOUT_MIGRATIONS", False):
    MIGRATION_MODULES = {
        app.split(".")[-1]: None
        for app in INSTALLED_APPS
        if app not in ["replication_utils"]
    }

Create db based on models

Detect testing mode

import sys

TESTING = len(sys.argv) > 1 and sys.argv[1] == 'test'

Speedup indivudal tests

https://github.com/realpython/django-slow-tests

Speedup indivudal tests

TEST_RUNNER = 'django_slowtests.testrunner.DiscoverSlowestTestsRunner'
NUM_SLOW_TESTS = 10

Find slow tests

Speedup indivudal tests

Mock requests

class BaseMockTestCase(SimpleTestCase):
    def setUp(self) -> None:
        self.requests_mock = requests_mock.mock()
        self.requests_mock.start()
        self.addCleanup(self.requests_mock.stop)
        super().setUp()

TestCase vs TransactionTestCase

(Avoid TransactionTestCase)

 

Speedup indivudal tests

Hit the db only when necessary

Speedup indivudal tests

Avoid fixtures

Use factories (faster and can evolve)

Speedup indivudal tests

Postgresql

fsync = off
synchronous_commit = off
full_page_writes = off

Postgresql

https://gist.github.com/mlavin/2053678

UNLOGGED TABLE

Thank You

Made with Slides.com