I'm testing my Django application with Selenium in Docker. I encounter a peculiar thing related to cookies availability (I use cookies to authenticate in my tests).
Here is the code that works:
from django.contrib.staticfiles.testing import StaticLiveServerTestCase
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from users.models import CustomUser
class SomeTest(StaticLiveServerTestCase):
#classmethod
def setUpClass(cls):
cls.host = "web" # Docker service name
super().setUpClass()
CustomUser.objects.create_user(username="user", password="password")
def setUp(self):
self.browser = webdriver.Remote("http://selenium:4444/wd/hub", DesiredCapabilities.FIREFOX)
def tearDown(self):
self.browser.quit()
def test2(self):
self.client.login(username="user", password="password")
cookie = self.client.cookies["sessionid"]
...
However, when I insert there another test case before test2, let it be something as simple as
def test1(self):
pass
then the code crashes with the following error:
Traceback (most recent call last):
File "/home/mysite/functional_tests/test.py", line 28, in test2
cookie = self.client.cookies["sessionid"]
KeyError: 'sessionid'
So the only difference between the working and not-working code is a dummy test function, but what does it change? As far as I know the setUp and tearDown methods make sure that the "environment" is the same for every test case, no matter what happens in other test methods and here it clearly depends on the (non-)existence of other test cases before running my test... Is there something I misunderstand? Or is it some kind of a bug?
Any help will be appreciated.
My setup:
Django==2.2.5
selenium==3.141.0
Docker version - 19.03.5
I've solved it and I'm posting the answer here in case anyone else encounters similar issues.
So the problem here was not with test case order, Docker, Selenium, or anything within the code itself but with my lack of understanding of how class StaticLiveServerTestCase behaves. Namely, this class inherits from LiveServerTestCase which in turn inherits from TransactionTestCase which tears down the database after each test case (and sets it up before another test case) - more on this can be found in Django docs. And as I was creating the user in setUpClass - which is run once per all the test cases in the class - it was indeed created but removed (together with the whole database) after any first test case. Sowhen I was doing self.client.login(username="user", password="password") it was not a problem with cookies or authentication per se but with the fact that the user simply didn't exist.
:-)
I am trying to run a simple unit test in Django where I verify the template used. It is very similar to the test in TDD with Django:
from django.test import TestCase
class HomePageTest(TestCase):
def test_uses_home_template(self):
response = self.client.get('/')
self.assertTemplateUsed(response, 'home.html')
The problem is that the view uses a second database and it fails with the error:
django.db.utils.ProgrammingError: relation "public.secondary_db" does not exist
Is it possible to run this test without hitting the database at all? I know that multiple databases in Django is a known issue, but is there a way to avoid this issue all together?
I'm writing the tests for django views, Some of the views are making the external HTTP requests. While running the tests i dont want to execute these HTTP requests. Since during tests , data is being used is dummy and these HTTP requests will not behave as expected.
What could be the possible options for this ?
You could override settings in your tests and then check for that setting in your view. Here are the docs to override settings.
from django.conf import settings
if not settings.TEST_API:
# api call here
Then your test would look something like this
from django.test import TestCase, override_settings
class LoginTestCase(TestCase):
#override_settings(TEST_API=True)
def test_api_func(self):
# Do test here
Since it would be fairly messy to have those all over the place I would recommend creating a mixin that would look something like this.
class SensitiveAPIMixin(object):
def api_request(self, url, *args, **kwargs):
from django.conf import settings
if not settings.TEST_API:
request = api_call(url)
# Do api request in here
return request
Then, through the power of multiple inheritence, your views that you need to make a request to this api call you could do something similar to this.
class View(generic.ListView, SensitiveAPIMixin):
def get(self, request, *args, **kwargs):
data = self.api_request('http://example.com/api1')
This is where mocking comes in. In your tests, you can use libraries to patch the parts of the code you are testing to return the results you expect for the test, bypassing what that code actually does.
You can read a good blog post about mocking in Python here.
If you are on Python 3.3 or later, the mock library is included in Python. If not, you can download it from PyPI.
The exact details of how to mock the calls you're making will depend on what exactly your view code looks like.
Ben is right on, but here's some psuedo-ish code that might help. The patch here assumes you're using requests, but change the path as necessary to mock out what you need.
from unittest import mock
from django.test import TestCase
from django.core.urlresolvers import reverse
class MyTestCase(TestCase):
#mock.patch('requests.post') # this is all you need to stop the API call
def test_my_view_that_posts_to_an_api(self, mock_get):
response = self.client.get(reverse('my-view-name'))
self.assertEqual('my-value', response.data['my-key'])
# other assertions as necessary
I have some external services. My Django app is built on top of my external service APIs. In order to talk to my external service, I have to pass in an auth cookies, which I can get by reading User (that cookie != django cookies).
Using test tools like webtests, requests, I have trouble writing my tests.
class MyTestCase(WebTest):
def test_my_view(self):
#client = Client()
#response = client.get(reverse('create')).form
form = self.app.get(reverse('create'), user='dummy').form
print form.fields.values()
form['name'] = 'omghell0'
print form
response = form.submit()
I need to submit a form, which creates, say, a user on my external service. But to do that, I normally would pass in request.user (in order to authenticate my privilege to external service). But I don't have request.user.
What options do I have for this kind of stuff?
Thanks...
Suppose this is my tests.py
import unittest
from django.test.client import Client
from django.core.urlresolvers import reverse
from django_webtest import WebTest
from django.contrib.auth.models import User
class SimpleTest(unittest.TestCase):
def setUp(self):
self.usr = User.objects.get(username='dummy')
print self.usr
.......
I get
Traceback (most recent call last):
File "/var/lib/graphyte-webclient/webclient/apps/codebundles/tests.py", line 10, in setUp
self.usr = User.objects.get(username='dummy')
File "/var/lib/graphyte-webclient/graphyte-webenv/lib/python2.6/site-packages/django/db/models/manager.py", line 132, in get
return self.get_query_set().get(*args, **kwargs)
File "/var/lib/graphyte-webclient/graphyte-webenv/lib/python2.6/site-packages/django/db/models/query.py", line 341, in get
% self.model._meta.object_name)
DoesNotExist: User matching query does not exist
But if I test the User.objects in views, I am okay.
You need to use the setUp() method to create test users for testing - testing never uses live data, but creates a temporary test database to run your unit tests. Read this for more information: https://docs.djangoproject.com/en/dev/topics/testing/?from=olddocs#writing-unit-tests
EDIT:
Here's an example:
from django.utils import unittest
from django.contrib.auth.models import User
from myapp.models import ThisModel, ThatModel
class ModelTest(unittest.TestCase):
def setUp(self):
# Create some users
self.user_1 = User.objects.create_user('Chevy Chase', 'chevy#chase.com', 'chevyspassword')
self.user_2 = User.objects.create_user('Jim Carrey', 'jim#carrey.com', 'jimspassword')
self.user_3 = User.objects.create_user('Dennis Leary', 'dennis#leary.com', 'denisspassword')
Also note that, if you are going to use more than one method to test different functionality, you should use the tearDown method to destroy objects before reinstantiating them for the next test. This is something that took me a while to finally figure out, so I'll save you the trouble.
def tearDown(self):
# Clean up after each test
self.user_1.delete()
self.user_2.delete()
self.user_3.delete()
Django recommends using either unit tests or doc tests, as described here. You can put these tests into tests.py in each apps directory, and they will run when the command `python manage.py test" is used.
Django provides very helpful classes and functions for unit testing, as described here. In particular, the class django.test.Client is very convenient, and lets you control things like users.
https://docs.djangoproject.com/en/1.4/topics/testing/#module-django.test.client
Use the django test client to simulate requests. If you need to test the behavior of the returned result then use Selenium.
Is there a possibility to write django unittests without setting up a db? I want to test business logic which doesn't require the db to set up. And while it is fast to setup a db, I really don't need it in some situations.
You can subclass DjangoTestSuiteRunner and override setup_databases and teardown_databases methods to pass.
Create a new settings file and set TEST_RUNNER to the new class you just created. Then when you're running your test, specify your new settings file with --settings flag.
Here is what I did:
Create a custom test suit runner similar to this:
from django.test.simple import DjangoTestSuiteRunner
class NoDbTestRunner(DjangoTestSuiteRunner):
""" A test runner to test without database creation """
def setup_databases(self, **kwargs):
""" Override the database creation defined in parent class """
pass
def teardown_databases(self, old_config, **kwargs):
""" Override the database teardown defined in parent class """
pass
Create a custom settings:
from mysite.settings import *
# Test runner with no database creation
TEST_RUNNER = 'mysite.scripts.testrunner.NoDbTestRunner'
When you're running your tests, run it like the following with --settings flag set to your new settings file:
python manage.py test myapp --settings='no_db_settings'
UPDATE: April/2018
Since Django 1.8, the module django.test.simple.DjangoTestSuiteRunner were moved to 'django.test.runner.DiscoverRunner'.
For more info check official doc section about custom test runners.
Generally tests in an application can be classified in to two categories
Unit tests, these test the individual snippets of code in insolation and do not require to go to the database
Integration test cases which actually go to the database and test the fully integrated logic.
Django supports both unit and integration tests.
Unit tests, do not require to setup and tear down database and these we should inherit from SimpleTestCase.
from django.test import SimpleTestCase
class ExampleUnitTest(SimpleTestCase):
def test_something_works(self):
self.assertTrue(True)
For integration test cases inherit from TestCase in turn inherits from TransactionTestCase and it will setup and tear down the database before running each test.
from django.test import TestCase
class ExampleIntegrationTest(TestCase):
def test_something_works(self):
#do something with database
self.assertTrue(True)
This strategy will ensure that database in created and destroyed only for the test cases that access the database and therefore tests will be more efficient
From django.test.simple
warnings.warn(
"The django.test.simple module and DjangoTestSuiteRunner are deprecated; "
"use django.test.runner.DiscoverRunner instead.",
RemovedInDjango18Warning)
So override DiscoverRunner instead of DjangoTestSuiteRunner.
from django.test.runner import DiscoverRunner
class NoDbTestRunner(DiscoverRunner):
""" A test runner to test without database creation/deletion """
def setup_databases(self, **kwargs):
pass
def teardown_databases(self, old_config, **kwargs):
pass
Use like that :
python manage.py test --testrunner=app.filename.NoDbTestRunner app
I chose to inherit from django.test.runner.DiscoverRunner and make a couple of additions to the run_tests method.
My first addition checks to see if setting up a db is necessary and allows the normal setup_databases functionality to kick in if a db is necessary. My second addition allows the normal teardown_databases to run if the setup_databases method was allowed to run.
My code assumes that any TestCase that inherits from django.test.TransactionTestCase (and thus django.test.TestCase) requires a database to be setup. I made this assumption because the Django docs say:
If you need any of the other more complex and heavyweight Django-specific features like ... Testing or using the ORM ... then you should use TransactionTestCase or TestCase instead.
https://docs.djangoproject.com/en/1.6/topics/testing/tools/#django.test.SimpleTestCase
mysite/scripts/settings.py
from django.test import TransactionTestCase
from django.test.runner import DiscoverRunner
class MyDiscoverRunner(DiscoverRunner):
def run_tests(self, test_labels, extra_tests=None, **kwargs):
"""
Run the unit tests for all the test labels in the provided list.
Test labels should be dotted Python paths to test modules, test
classes, or test methods.
A list of 'extra' tests may also be provided; these tests
will be added to the test suite.
If any of the tests in the test suite inherit from
``django.test.TransactionTestCase``, databases will be setup.
Otherwise, databases will not be set up.
Returns the number of tests that failed.
"""
self.setup_test_environment()
suite = self.build_suite(test_labels, extra_tests)
# ----------------- First Addition --------------
need_databases = any(isinstance(test_case, TransactionTestCase)
for test_case in suite)
old_config = None
if need_databases:
# --------------- End First Addition ------------
old_config = self.setup_databases()
result = self.run_suite(suite)
# ----------------- Second Addition -------------
if need_databases:
# --------------- End Second Addition -----------
self.teardown_databases(old_config)
self.teardown_test_environment()
return self.suite_result(suite, result)
Finally, I added the following line to my project's settings.py file.
mysite/settings.py
TEST_RUNNER = 'mysite.scripts.settings.MyDiscoverRunner'
Now, when running only non-db-dependent tests, my test suite runs an order of magnitude faster! :)
Updated: also see this answer for using a third-party tool pytest.
#Cesar is right. After accidentally running ./manage.py test --settings=no_db_settings, without specifying an app name, my development database was wiped out.
For a safer manner, use the same NoDbTestRunner, but in conjunction with the following mysite/no_db_settings.py:
from mysite.settings import *
# Test runner with no database creation
TEST_RUNNER = 'mysite.scripts.testrunner.NoDbTestRunner'
# Use an alternative database as a safeguard against accidents
DATABASES['default']['NAME'] = '_test_mysite_db'
You need to create a database called _test_mysite_db using an external database tool. Then run the following command to create the corresponding tables:
./manage.py syncdb --settings=mysite.no_db_settings
If you're using South, also run the following command:
./manage.py migrate --settings=mysite.no_db_settings
OK!
You can now run unit tests blazingly fast (and safe) by:
./manage.py test myapp --settings=mysite.no_db_settings
As an alternative to modifying your settings to make NoDbTestRunner "safe", here's a modified version of NoDbTestRunner that closes the current database connection and removes the connection information from settings and the connection object. Works for me, test it in your environment before relying on it :)
class NoDbTestRunner(DjangoTestSuiteRunner):
""" A test runner to test without database creation """
def __init__(self, *args, **kwargs):
# hide/disconnect databases to prevent tests that
# *do* require a database which accidentally get
# run from altering your data
from django.db import connections
from django.conf import settings
connections.databases = settings.DATABASES = {}
connections._connections['default'].close()
del connections._connections['default']
super(NoDbTestRunner,self).__init__(*args,**kwargs)
def setup_databases(self, **kwargs):
""" Override the database creation defined in parent class """
pass
def teardown_databases(self, old_config, **kwargs):
""" Override the database teardown defined in parent class """
pass
Another solution would be to have your test class simply inherit from unittest.TestCase instead of any of Django's test classes. The Django docs (https://docs.djangoproject.com/en/2.0/topics/testing/overview/#writing-tests) contain the following warning about this:
Using unittest.TestCase avoids the cost of running each test in a transaction and flushing the database, but if your tests interact with the database their behavior will vary based on the order that the test runner executes them. This can lead to unit tests that pass when run in isolation but fail when run in a suite.
However, if your test doesn't use the database, this warning needn't concern you and you can reap the benefits of not having to run each test case in a transaction.
The above solutions are fine too. But the following solution will also reduce the db creation time if there are more number of migrations.
During unit testing, running syncdb instead of running all the south migrations will be much faster.
SOUTH_TESTS_MIGRATE = False # To disable migrations and use syncdb
instead
My web host only allows creating and dropping databases from their Web GUI, so I was getting a "Got an error creating the test database: Permission denied" error when trying to run python manage.py test.
I'd hoped to use the --keepdb option to django-admin.py but it doesn't seem to be supported any longer as of Django 1.7.
What I ended up doing was modifying the Django code in .../django/db/backends/creation.py, specifically the _create_test_db and _destroy_test_db functions.
For _create_test_db I commented out the cursor.execute("CREATE DATABASE ... line and replaced it with pass so the try block wouldn't be empty.
For _destroy_test_db I just commented out cursor.execute("DROP DATABASE - I didn't need to replace it with anything because there was already another command in the block (time.sleep(1)).
After that my tests ran fine - though I did set up a test_ version of my regular database separately.
This isn't a great solution of course, because it will break if Django is upgraded, but I had a local copy of Django due to using virtualenv so at least I have control over when/if I upgrade to a newer version.
Another solution not mentioned: this was easy for me to implement because I already have multiple settings files (for local / staging / production) that inherit from base.py . So unlike other people I did not have to overwrite DATABASES['default'], as DATABASES isn't set in base.py
SimpleTestCase still tried to connect to my test database and run migrations. When I made a config/settings/test.py file that didn't set DATABASES to anything, then my unit tests ran without it. It allowed me to use models that had foreign key and unique constraint fields. (Reverse foreign key lookup, which requires a db lookup, fails.)
(Django 2.0.6)
PS code snippets
PROJECT_ROOT_DIR/config/settings/test.py:
from .base import *
#other test settings
#DATABASES = {
# 'default': {
# 'ENGINE': 'django.db.backends.sqlite3',
# 'NAME': 'PROJECT_ROOT_DIR/db.sqlite3',
# }
#}
cli, run from PROJECT_ROOT_DIR:
./manage.py test path.to.app.test --settings config.settings.test
path/to/app/test.py:
from django.test import SimpleTestCase
from .models import *
#^assume models.py imports User and defines Classified and UpgradePrice
class TestCaseWorkingTest(SimpleTestCase):
def test_case_working(self):
self.assertTrue(True)
def test_models_ok(self):
obj = UpgradePrice(title='test',price=1.00)
self.assertEqual(obj.title,'test')
def test_more_complex_model(self):
user = User(username='testuser',email='hi#hey.com')
self.assertEqual(user.username,'testuser')
def test_foreign_key(self):
user = User(username='testuser',email='hi#hey.com')
ad = Classified(user=user,headline='headline',body='body')
self.assertEqual(ad.user.username,'testuser')
#fails with error:
def test_reverse_foreign_key(self):
user = User(username='testuser',email='hi#hey.com')
ad = Classified(user=user,headline='headline',body='body')
print(user.classified_set.first())
self.assertTrue(True) #throws exception and never gets here
When using the nose test runner (django-nose), you can do something like this:
my_project/lib/nodb_test_runner.py:
from django_nose import NoseTestSuiteRunner
class NoDbTestRunner(NoseTestSuiteRunner):
"""
A test runner to test without database creation/deletion
Used for integration tests
"""
def setup_databases(self, **kwargs):
pass
def teardown_databases(self, old_config, **kwargs):
pass
In your settings.py you can specify the test runner there, i.e.
TEST_RUNNER = 'lib.nodb_test_runner.NoDbTestRunner' . # Was 'django_nose.NoseTestSuiteRunner'
OR
I wanted it for running specific tests only, so I run it like so:
python manage.py test integration_tests/integration_* --noinput --testrunner=lib.nodb_test_runner.NoDbTestRunner
You can set databases to an empty list inside the normal TestCase from django.test.
from django.test import TestCase
class NoDbTestCase(TestCase):
databases = []