Django Unit Testing Testing Django Models Effectively
Example
Assuming a class
from django.db import models
class Author(models.Model):
name = models.CharField(max_length=50)
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse('view_author', args=[str(self.id)])
class Book(models.Model):
author = models.ForeignKey(Manufacturer, on_delete=models.CASCADE)
private = models.BooleanField(default=false)
publish_date = models.DateField()
def get_absolute_url(self):
return reverse('view_book', args=[str(self.id)])
def __str__(self):
return self.name
Testing examples
from django.test import TestCase
from .models import Book, Author
class BaseModelTestCase(TestCase):
@classmethod
def setUpClass(cls):
super(BaseModelTestCase, cls).setUpClass()
cls.author = Author(name='hawking')
cls.author.save()
cls.first_book = Book(author=cls.author, name="short_history_of_time")
cls.first_book.save()
cls.second_book = Book(author=cls.author, name="long_history_of_time")
cls.second_book.save()
class AuthorModelTestCase(BaseModelTestCase):
def test_created_properly(self):
self.assertEqual(self.author.name, 'hawking')
self.assertEqual(True, self.first_book in self.author.book_set.all())
def test_absolute_url(self):
self.assertEqual(self.author.get_absolute_url(), reverse('view_author', args=[str(self.author.id)]))
class BookModelTestCase(BaseModelTestCase):
def test_created_properly(self:
...
self.assertEqual(1, len(Book.objects.filter(name__startswith='long'))
def test_absolute_url(self):
...
Some points
created_properlytests are used to verify the state properties of django models. They help catch sitautions where we've changed default values, file_upload_paths etc.absolute_urlmight seem trivial but I've found that it's helped me prevent some bugs when changing url paths- I similarly write test cases for all the methods implemented inside a model (using
mockobjects etc) - By defining a common
BaseModelTestCasewe can setup the necessary relationships between models to ensure proper testing.
Finally, when in doubt, write a test. Trivial behavior changes are caught by paying attention to detail and long forgotten pieces of code don't end up causing unnecessary trouble.
