Basic Django project tests

2024-02-18 | Tag python django tests

Django’s automated testing framework extends Python’s unit testing framework unittest with multiple additions into a web context.

Test file location

We write unit tests in tests.py file under Django app.

Unit tests

We create unit tests by extending django.tests.TestCase.

Each method must be prefaced with test in order to be run by the Django test suite.

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

class CustomUserTests(TestCase):
    def test_create_user(self):
		pass

Authentication

Use TestCase’s client to login and logout:

self.client.login(username="name", password="pass")
self.client.logout()

Test web pages that do not have a model included

django.tests.SimpleTestCase is a special subset of TestCase that is designed for web pages that does not involve any database queries.

We can use TestCase’s client to visit URL: self.client.get(url).

from django.test import SimpleTestCase
from django.urls import reverse

class HomepageTests(SimpleTestCase):
    def test_url_exists_at_correct_location(self):
        response = self.client.get('/')
        self.assertEqual(response.status_code, 200)

Test templates

Use assertTemplateUsed(response, template_name):

from django.test import SimpleTestCase
from django.urls import reverse

class HomepageTests(SimpleTestCase):
    def test_homepage_template(self):
        response = self.client.get('/')
        self.assertTemplateUsed(response, 'home.html')

Test HTML content

Use assertContains(response, text) and `assertNotContains(response, text):

from django.test import SimpleTestCase
from django.urls import reverse

class HomepageTests(SimpleTestCase):
    def test_homepage_contains_correct_html(self):
        response = self.client.get('/')
        self.assertContains(response, 'home page')

    def test_homepage_not_contains_incorrect_html(self):
        response = self.client.get('/')
        self.assertNotContains(response, 'Hi there! I should not be on the page.')

Test context

We can get context variable from response.context:

class SignUpPageTests(TestCase):
    def setUp(self):
        url = reverse('signup')
        self.response = self.client.get(url)

    def test_signup_form(self):
        form = self.response.context.get('form')
        self.assertIsInstance(form, CustomUserCreationForm)
        self.assertContains(self.response, 'csrfmiddlewaretoken')

DRY with setUp()

setUp() is called before running each unit test.

We can extract the same steps from test methods into setUp().

from django.test import SimpleTestCase
from django.urls import reverse

class HomepageTests(SimpleTestCase):
    def setUp(self):
        url = reverse('home')
        self.response = self.client.get(url)

    def test_url_exists_at_correct_location(self):
        self.assertEqual(self.response.status_code, 200)

Set up init data with setUpTestData() at class level

from django.test import TestCase
from django.urls import reverse
from .models import Book

class BookTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        cls.book = Book.objects.create(
            title = "Harry Potter",
            author="JK Powling",
            price="25.00",
        )

Using setUpTestData often dramatically increases the speed of tests because the initial data is created once rather than each time for each unit test.

resolve test

resolve(path) function can be used for resolving URL paths to the corresponding view functions, while reverse(url_name) function can be used for getting the URL path from URL name.

from django.test import SimpleTestCase
from django.urls import reverse, resolve
from .views import HomePageView

class HomepageTests(SimpleTestCase):
    def setUp(self):
        url = reverse('home')
        self.response = self.client.get(url)

    def test_homepage_url_resolves_homepageview(self):
        view = resolve('/')
        self.assertEqual(view.func.__name__, HomePageView.as_view().__name__)

Some assertion method

assertEqual
assertTrue
assertFalse
assertTemplateUsed
assertContains
assertNotContains
self.assertIsInstance
self.assertRedirects

from django.test import SimpleTestCase
from django.urls import reverse, resolve

from .views import HomePageView

class HomepageTests(SimpleTestCase):

    def setUp(self):
        url = reverse('home')
        self.response = self.client.get(url)

    def test_url_exists_at_correct_location(self):
        self.assertEqual(self.response.status_code, 200)

    def test_homepage_template(self):
        self.assertTemplateUsed(self.response, 'home.html')

    def test_homepage_contains_correct_html(self):
        self.assertContains(self.response, 'home page')

    def test_homepage_not_contains_incorrect_html(self):
        self.assertNotContains(self.response, 'Hi there! I should not be on the page.')

    def test_homepage_url_resolves_homepageview(self):
        view = resolve('/')
        self.assertEqual(view.func.__name__, HomePageView.as_view().__name__)

Necessary tests for a html page

test_page_status_code()
test_page_template()
test_page_contains_correct_html()
test_page_not_contains_incorrect_html()
test_page_url_resolves_to_correct_view()

Necessary tests for model based page

set up init data with setupTestData(cls)
test_object_listing(): test string representations of model field and model instance itself.
test_object_list_view()
test_object_detail_view()

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