Testing

Django · Reference cheat sheet

📋 Overview

Django ships TestCase, SimpleTestCase, TransactionTestCase, and LiveServerTestCase on top of unittest. Prefer TestCase for DB tests (wraps each test in a transaction). Use the test client for request/response; factories or fixtures for data.

🔧 Core concepts

Class	Use
`SimpleTestCase`	No DB
`TestCase`	DB + rollback per test
`TransactionTestCase`	Real commits (signals, threads)
`APITestCase`	DRF (if installed)
Client	`self.client.get/post`
`override_settings`	Temporary settings
`assertNumQueries`	Catch N+1

Run: python manage.py test or pytest + pytest-django.

💡 Examples

View test:

from django.test import TestCase
from django.urls import reverse
from django.contrib.auth import get_user_model

from blog.models import Article


class ArticleTests(TestCase):
    def setUp(self):
        User = get_user_model()
        self.user = User.objects.create_user("ada", password="x")
        self.article = Article.objects.create(
            title="Hi", slug="hi", body="...", author=self.user, is_published=True
        )

    def test_detail_ok(self):
        url = reverse("article-detail", kwargs={"slug": "hi"})
        response = self.client.get(url)
        self.assertEqual(response.status_code, 200)
        self.assertContains(response, "Hi")

    def test_create_requires_login(self):
        url = reverse("article-create")
        response = self.client.post(url, {"title": "X", "slug": "x", "body": "y"})
        self.assertEqual(response.status_code, 302)

Query count:

def test_list_queries(self):
    with self.assertNumQueries(2):  # adjust to reality
        self.client.get(reverse("article-list"))

Settings override:

from django.test import override_settings

@override_settings(EMAIL_BACKEND="django.core.mail.backends.locmem.EmailBackend")
def test_sends_mail(self):
    ...

⚠️ Pitfalls

Sharing mutable state across tests without isolation.
Hitting real email/SMS/payment APIs—mock or use locmem backends.
TransactionTestCase is slower; use only when needed.
Hardcoding absolute URLs—use reverse.
Flaky time-dependent tests—freeze time or use freezegun.

Testing

Testing

📋 Overview

🔧 Core concepts

💡 Examples

⚠️ Pitfalls

🔗 Related

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