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===========================
Testing Django applications
===========================
.. module:: django.test
:synopsis: Testing tools for Django applications.
.. seealso::
The :doc:`testing tutorial </intro/tutorial05>` and the
:doc:`advanced testing topics </topics/testing/advanced>`.
This document is split into two primary sections. First, we explain how to write
tests with Django. Then, we explain how to run them.
Writing tests
=============
Django's unit tests use a Python standard library module: :mod:`unittest`. This
module defines tests using a class-based approach.
.. admonition:: unittest2
.. deprecated:: 1.7
Python 2.7 introduced some major changes to the ``unittest`` library,
adding some extremely useful features. To ensure that every Django project
could benefit from these new features, Django used to ship with a copy of
Python 2.7's ``unittest`` backported for Python 2.6 compatibility.
Since Django no longer supports Python versions older than 2.7,
``django.utils.unittest`` is deprecated. Simply use ``unittest``.
.. _unittest2: http://pypi.python.org/pypi/unittest2
Here is an example which subclasses from :class:`django.test.TestCase`,
which is a subclass of :class:`unittest.TestCase` that runs each test inside a
transaction to provide isolation::
from django.test import TestCase
from myapp.models import Animal
class AnimalTestCase(TestCase):
def setUp(self):
Animal.objects.create(name="lion", sound="roar")
Animal.objects.create(name="cat", sound="meow")
def test_animals_can_speak(self):
"""Animals that can speak are correctly identified"""
lion = Animal.objects.get(name="lion")
cat = Animal.objects.get(name="cat")
self.assertEqual(lion.speak(), 'The lion says "roar"')
self.assertEqual(cat.speak(), 'The cat says "meow"')
When you :ref:`run your tests <running-tests>`, the default behavior of the
test utility is to find all the test cases (that is, subclasses of
:class:`unittest.TestCase`) in any file whose name begins with ``test``,
automatically build a test suite out of those test cases, and run that suite.
.. versionchanged:: 1.6
Previously, Django's default test runner only discovered tests in
``tests.py`` and ``models.py`` files within a Python package listed in
:setting:`INSTALLED_APPS`.
For more details about :mod:`unittest`, see the Python documentation.
.. warning::
If your tests rely on database access such as creating or querying models,
be sure to create your test classes as subclasses of
:class:`django.test.TestCase` rather than :class:`unittest.TestCase`.
Using :class:`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.
.. _running-tests:
Running tests
=============
Once you've written tests, run them using the :djadmin:`test` command of
your project's ``manage.py`` utility::
$ ./manage.py test
Test discovery is based on the unittest module's :py:ref:`built-in test
discovery <unittest-test-discovery>`. By default, this will discover tests in
any file named "test*.py" under the current working directory.
You can specify particular tests to run by supplying any number of "test
labels" to ``./manage.py test``. Each test label can be a full Python dotted
path to a package, module, ``TestCase`` subclass, or test method. For instance::
# Run all the tests in the animals.tests module
$ ./manage.py test animals.tests
# Run all the tests found within the 'animals' package
$ ./manage.py test animals
# Run just one test case
$ ./manage.py test animals.tests.AnimalTestCase
# Run just one test method
$ ./manage.py test animals.tests.AnimalTestCase.test_animals_can_speak
You can also provide a path to a directory to discover tests below that
directory::
$ ./manage.py test animals/
You can specify a custom filename pattern match using the ``-p`` (or
``--pattern``) option, if your test files are named differently from the
``test*.py`` pattern::
$ ./manage.py test --pattern="tests_*.py"
.. versionchanged:: 1.6
Previously, test labels were in the form ``applabel``,
``applabel.TestCase``, or ``applabel.TestCase.test_method``, rather than
being true Python dotted paths, and tests could only be found within
``tests.py`` or ``models.py`` files within a Python package listed in
:setting:`INSTALLED_APPS`. The ``--pattern`` option and file paths as test
labels are new in 1.6.
If you press ``Ctrl-C`` while the tests are running, the test runner will
wait for the currently running test to complete and then exit gracefully.
During a graceful exit the test runner will output details of any test
failures, report on how many tests were run and how many errors and failures
were encountered, and destroy any test databases as usual. Thus pressing
``Ctrl-C`` can be very useful if you forget to pass the :djadminopt:`--failfast`
option, notice that some tests are unexpectedly failing, and want to get details
on the failures without waiting for the full test run to complete.
If you do not want to wait for the currently running test to finish, you
can press ``Ctrl-C`` a second time and the test run will halt immediately,
but not gracefully. No details of the tests run before the interruption will
be reported, and any test databases created by the run will not be destroyed.
.. admonition:: Test with warnings enabled
It's a good idea to run your tests with Python warnings enabled:
``python -Wall manage.py test``. The ``-Wall`` flag tells Python to
display deprecation warnings. Django, like many other Python libraries,
uses these warnings to flag when features are going away. It also might
flag areas in your code that aren't strictly wrong but could benefit
from a better implementation.
.. _the-test-database:
The test database
-----------------
Tests that require a database (namely, model tests) will not use your "real"
(production) database. Separate, blank databases are created for the tests.
Regardless of whether the tests pass or fail, the test databases are destroyed
when all the tests have been executed.
By default the test databases get their names by prepending ``test_``
to the value of the :setting:`NAME` settings for the databases
defined in :setting:`DATABASES`. When using the SQLite database engine
the tests will by default use an in-memory database (i.e., the
database will be created in memory, bypassing the filesystem
entirely!). If you want to use a different database name, specify
:setting:`TEST_NAME` in the dictionary for any given database in
:setting:`DATABASES`.
Aside from using a separate database, the test runner will otherwise
use all of the same database settings you have in your settings file:
:setting:`ENGINE <DATABASE-ENGINE>`, :setting:`USER`, :setting:`HOST`, etc. The
test database is created by the user specified by :setting:`USER`, so you'll
need to make sure that the given user account has sufficient privileges to
create a new database on the system.
For fine-grained control over the character encoding of your test
database, use the :setting:`TEST_CHARSET` option. If you're using
MySQL, you can also use the :setting:`TEST_COLLATION` option to
control the particular collation used by the test database. See the
:doc:`settings documentation </ref/settings>` for details of these
advanced settings.
.. admonition:: Finding data from your production database when running tests?
If your code attempts to access the database when its modules are compiled,
this will occur *before* the test database is set up, with potentially
unexpected results. For example, if you have a database query in
module-level code and a real database exists, production data could pollute
your tests. *It is a bad idea to have such import-time database queries in
your code* anyway - rewrite your code so that it doesn't do this.
.. seealso::
The :ref:`advanced multi-db testing topics <topics-testing-advanced-multidb>`.
.. _order-of-tests:
Order in which tests are executed
---------------------------------
In order to guarantee that all ``TestCase`` code starts with a clean database,
the Django test runner reorders tests in the following way:
* All :class:`~django.test.TestCase` subclasses are run first.
* Then, all other unittests (including :class:`unittest.TestCase`,
:class:`~django.test.SimpleTestCase` and
:class:`~django.test.TransactionTestCase`) are run with no particular
ordering guaranteed nor enforced among them.
* Then any other tests (e.g. doctests) that may alter the database without
restoring it to its original state are run.
.. note::
The new ordering of tests may reveal unexpected dependencies on test case
ordering. This is the case with doctests that relied on state left in the
database by a given :class:`~django.test.TransactionTestCase` test, they
must be updated to be able to run independently.
Other test conditions
---------------------
Regardless of the value of the :setting:`DEBUG` setting in your configuration
file, all Django tests run with :setting:`DEBUG`\=False. This is to ensure that
the observed output of your code matches what will be seen in a production
setting.
Caches are not cleared after each test, and running "manage.py test fooapp" can
insert data from the tests into the cache of a live system if you run your
tests in production because, unlike databases, a separate "test cache" is not
used. This behavior `may change`_ in the future.
.. _may change: https://code.djangoproject.com/ticket/11505
Understanding the test output
-----------------------------
When you run your tests, you'll see a number of messages as the test runner
prepares itself. You can control the level of detail of these messages with the
``verbosity`` option on the command line::
Creating test database...
Creating table myapp_animal
Creating table myapp_mineral
Loading 'initial_data' fixtures...
No fixtures found.
This tells you that the test runner is creating a test database, as described
in the previous section.
Once the test database has been created, Django will run your tests.
If everything goes well, you'll see something like this::
----------------------------------------------------------------------
Ran 22 tests in 0.221s
OK
If there are test failures, however, you'll see full details about which tests
failed::
======================================================================
FAIL: test_was_published_recently_with_future_poll (polls.tests.PollMethodTests)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/dev/mysite/polls/tests.py", line 16, in test_was_published_recently_with_future_poll
self.assertEqual(future_poll.was_published_recently(), False)
AssertionError: True != False
----------------------------------------------------------------------
Ran 1 test in 0.003s
FAILED (failures=1)
A full explanation of this error output is beyond the scope of this document,
but it's pretty intuitive. You can consult the documentation of Python's
:mod:`unittest` library for details.
Note that the return code for the test-runner script is 1 for any number of
failed and erroneous tests. If all the tests pass, the return code is 0. This
feature is useful if you're using the test-runner script in a shell script and
need to test for success or failure at that level.
Speeding up the tests
---------------------
In recent versions of Django, the default password hasher is rather slow by
design. If during your tests you are authenticating many users, you may want
to use a custom settings file and set the :setting:`PASSWORD_HASHERS` setting
to a faster hashing algorithm::
PASSWORD_HASHERS = (
'django.contrib.auth.hashers.MD5PasswordHasher',
)
Don't forget to also include in :setting:`PASSWORD_HASHERS` any hashing
algorithm used in fixtures, if any.
Testing tools
=============
Django provides a small set of tools that come in handy when writing tests.
.. _test-client:
The test client
---------------
The test client is a Python class that acts as a dummy Web browser, allowing
you to test your views and interact with your Django-powered application
programmatically.
Some of the things you can do with the test client are:
* Simulate GET and POST requests on a URL and observe the response --
everything from low-level HTTP (result headers and status codes) to
page content.
* See the chain of redirects (if any) and check the URL and status code at
each step.
* Test that a given request is rendered by a given Django template, with
a template context that contains certain values.
Note that the test client is not intended to be a replacement for Selenium_ or
other "in-browser" frameworks. Django's test client has a different focus. In
short:
* Use Django's test client to establish that the correct template is being
rendered and that the template is passed the correct context data.
* Use in-browser frameworks like Selenium_ to test *rendered* HTML and the
*behavior* of Web pages, namely JavaScript functionality. Django also
provides special support for those frameworks; see the section on
:class:`~django.test.LiveServerTestCase` for more details.
A comprehensive test suite should use a combination of both test types.
Overview and a quick example
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To use the test client, instantiate ``django.test.Client`` and retrieve
Web pages::
>>> from django.test import Client
>>> c = Client()
>>> response = c.post('/login/', {'username': 'john', 'password': 'smith'})
>>> response.status_code
200
>>> response = c.get('/customer/details/')
>>> response.content
'<!DOCTYPE html...'
As this example suggests, you can instantiate ``Client`` from within a session
of the Python interactive interpreter.
Note a few important things about how the test client works:
* The test client does *not* require the Web server to be running. In fact,
it will run just fine with no Web server running at all! That's because
it avoids the overhead of HTTP and deals directly with the Django
framework. This helps make the unit tests run quickly.
* When retrieving pages, remember to specify the *path* of the URL, not the
whole domain. For example, this is correct::
>>> c.get('/login/')
This is incorrect::
>>> c.get('http://www.example.com/login/')
The test client is not capable of retrieving Web pages that are not
powered by your Django project. If you need to retrieve other Web pages,
use a Python standard library module such as :mod:`urllib` or
:mod:`urllib2`.
* To resolve URLs, the test client uses whatever URLconf is pointed-to by
your :setting:`ROOT_URLCONF` setting.
* Although the above example would work in the Python interactive
interpreter, some of the test client's functionality, notably the
template-related functionality, is only available *while tests are
running*.
The reason for this is that Django's test runner performs a bit of black
magic in order to determine which template was loaded by a given view.
This black magic (essentially a patching of Django's template system in
memory) only happens during test running.
* By default, the test client will disable any CSRF checks
performed by your site.
If, for some reason, you *want* the test client to perform CSRF
checks, you can create an instance of the test client that
enforces CSRF checks. To do this, pass in the
``enforce_csrf_checks`` argument when you construct your
client::
>>> from django.test import Client
>>> csrf_client = Client(enforce_csrf_checks=True)
Making requests
~~~~~~~~~~~~~~~
Use the ``django.test.Client`` class to make requests.
.. class:: Client(enforce_csrf_checks=False, **defaults)
It requires no arguments at time of construction. However, you can use
keywords arguments to specify some default headers. For example, this will
send a ``User-Agent`` HTTP header in each request::
>>> c = Client(HTTP_USER_AGENT='Mozilla/5.0')
The values from the ``extra`` keywords arguments passed to
:meth:`~django.test.Client.get()`,
:meth:`~django.test.Client.post()`, etc. have precedence over
the defaults passed to the class constructor.
The ``enforce_csrf_checks`` argument can be used to test CSRF
protection (see above).
Once you have a ``Client`` instance, you can call any of the following
methods:
.. method:: Client.get(path, data={}, follow=False, secure=False, **extra)
.. versionadded:: 1.7
The ``secure`` argument was added.
Makes a GET request on the provided ``path`` and returns a ``Response``
object, which is documented below.
The key-value pairs in the ``data`` dictionary are used to create a GET
data payload. For example::
>>> c = Client()
>>> c.get('/customers/details/', {'name': 'fred', 'age': 7})
...will result in the evaluation of a GET request equivalent to::
/customers/details/?name=fred&age=7
The ``extra`` keyword arguments parameter can be used to specify
headers to be sent in the request. For example::
>>> c = Client()
>>> c.get('/customers/details/', {'name': 'fred', 'age': 7},
... HTTP_X_REQUESTED_WITH='XMLHttpRequest')
...will send the HTTP header ``HTTP_X_REQUESTED_WITH`` to the
details view, which is a good way to test code paths that use the
:meth:`django.http.HttpRequest.is_ajax()` method.
.. admonition:: CGI specification
The headers sent via ``**extra`` should follow CGI_ specification.
For example, emulating a different "Host" header as sent in the
HTTP request from the browser to the server should be passed
as ``HTTP_HOST``.
.. _CGI: http://www.w3.org/CGI/
If you already have the GET arguments in URL-encoded form, you can
use that encoding instead of using the data argument. For example,
the previous GET request could also be posed as::
>>> c = Client()
>>> c.get('/customers/details/?name=fred&age=7')
If you provide a URL with both an encoded GET data and a data argument,
the data argument will take precedence.
If you set ``follow`` to ``True`` the client will follow any redirects
and a ``redirect_chain`` attribute will be set in the response object
containing tuples of the intermediate urls and status codes.
If you had a URL ``/redirect_me/`` that redirected to ``/next/``, that
redirected to ``/final/``, this is what you'd see::
>>> response = c.get('/redirect_me/', follow=True)
>>> response.redirect_chain
[(u'http://testserver/next/', 302), (u'http://testserver/final/', 302)]
If you set ``secure`` to ``True`` the client will emulate an HTTPS
request.
.. method:: Client.post(path, data={}, content_type=MULTIPART_CONTENT, follow=False, secure=False, **extra)
Makes a POST request on the provided ``path`` and returns a
``Response`` object, which is documented below.
The key-value pairs in the ``data`` dictionary are used to submit POST
data. For example::
>>> c = Client()
>>> c.post('/login/', {'name': 'fred', 'passwd': 'secret'})
...will result in the evaluation of a POST request to this URL::
/login/
...with this POST data::
name=fred&passwd=secret
If you provide ``content_type`` (e.g. :mimetype:`text/xml` for an XML
payload), the contents of ``data`` will be sent as-is in the POST
request, using ``content_type`` in the HTTP ``Content-Type`` header.
If you don't provide a value for ``content_type``, the values in
``data`` will be transmitted with a content type of
:mimetype:`multipart/form-data`. In this case, the key-value pairs in
``data`` will be encoded as a multipart message and used to create the
POST data payload.
To submit multiple values for a given key -- for example, to specify
the selections for a ``<select multiple>`` -- provide the values as a
list or tuple for the required key. For example, this value of ``data``
would submit three selected values for the field named ``choices``::
{'choices': ('a', 'b', 'd')}
Submitting files is a special case. To POST a file, you need only
provide the file field name as a key, and a file handle to the file you
wish to upload as a value. For example::
>>> c = Client()
>>> with open('wishlist.doc') as fp:
... c.post('/customers/wishes/', {'name': 'fred', 'attachment': fp})
(The name ``attachment`` here is not relevant; use whatever name your
file-processing code expects.)
Note that if you wish to use the same file handle for multiple
``post()`` calls then you will need to manually reset the file
pointer between posts. The easiest way to do this is to
manually close the file after it has been provided to
``post()``, as demonstrated above.
You should also ensure that the file is opened in a way that
allows the data to be read. If your file contains binary data
such as an image, this means you will need to open the file in
``rb`` (read binary) mode.
The ``extra`` argument acts the same as for :meth:`Client.get`.
If the URL you request with a POST contains encoded parameters, these
parameters will be made available in the request.GET data. For example,
if you were to make the request::
>>> c.post('/login/?visitor=true', {'name': 'fred', 'passwd': 'secret'})
... the view handling this request could interrogate request.POST
to retrieve the username and password, and could interrogate request.GET
to determine if the user was a visitor.
If you set ``follow`` to ``True`` the client will follow any redirects
and a ``redirect_chain`` attribute will be set in the response object
containing tuples of the intermediate urls and status codes.
If you set ``secure`` to ``True`` the client will emulate an HTTPS
request.
.. method:: Client.head(path, data={}, follow=False, secure=False, **extra)
Makes a HEAD request on the provided ``path`` and returns a
``Response`` object. This method works just like :meth:`Client.get`,
including the ``follow``, ``secure`` and ``extra`` arguments, except
it does not return a message body.
.. method:: Client.options(path, data='', content_type='application/octet-stream', follow=False, secure=False, **extra)
Makes an OPTIONS request on the provided ``path`` and returns a
``Response`` object. Useful for testing RESTful interfaces.
When ``data`` is provided, it is used as the request body, and
a ``Content-Type`` header is set to ``content_type``.
The ``follow``, ``secure`` and ``extra`` arguments act the same as for
:meth:`Client.get`.
.. method:: Client.put(path, data='', content_type='application/octet-stream', follow=False, secure=False, **extra)
Makes a PUT request on the provided ``path`` and returns a
``Response`` object. Useful for testing RESTful interfaces.
When ``data`` is provided, it is used as the request body, and
a ``Content-Type`` header is set to ``content_type``.
The ``follow``, ``secure`` and ``extra`` arguments act the same as for
:meth:`Client.get`.
.. method:: Client.patch(path, data='', content_type='application/octet-stream', follow=False, secure=False, **extra)
Makes a PATCH request on the provided ``path`` and returns a
``Response`` object. Useful for testing RESTful interfaces.
The ``follow``, ``secure`` and ``extra`` arguments act the same as for
:meth:`Client.get`.
.. method:: Client.delete(path, data='', content_type='application/octet-stream', follow=False, secure=False, **extra)
Makes an DELETE request on the provided ``path`` and returns a
``Response`` object. Useful for testing RESTful interfaces.
When ``data`` is provided, it is used as the request body, and
a ``Content-Type`` header is set to ``content_type``.
The ``follow``, ``secure`` and ``extra`` arguments act the same as for
:meth:`Client.get`.
.. method:: Client.login(**credentials)
If your site uses Django's :doc:`authentication system</topics/auth/index>`
and you deal with logging in users, you can use the test client's
``login()`` method to simulate the effect of a user logging into the
site.
After you call this method, the test client will have all the cookies
and session data required to pass any login-based tests that may form
part of a view.
The format of the ``credentials`` argument depends on which
:ref:`authentication backend <authentication-backends>` you're using
(which is configured by your :setting:`AUTHENTICATION_BACKENDS`
setting). If you're using the standard authentication backend provided
by Django (``ModelBackend``), ``credentials`` should be the user's
username and password, provided as keyword arguments::
>>> c = Client()
>>> c.login(username='fred', password='secret')
# Now you can access a view that's only available to logged-in users.
If you're using a different authentication backend, this method may
require different credentials. It requires whichever credentials are
required by your backend's ``authenticate()`` method.
``login()`` returns ``True`` if it the credentials were accepted and
login was successful.
Finally, you'll need to remember to create user accounts before you can
use this method. As we explained above, the test runner is executed
using a test database, which contains no users by default. As a result,
user accounts that are valid on your production site will not work
under test conditions. You'll need to create users as part of the test
suite -- either manually (using the Django model API) or with a test
fixture. Remember that if you want your test user to have a password,
you can't set the user's password by setting the password attribute
directly -- you must use the
:meth:`~django.contrib.auth.models.User.set_password()` function to
store a correctly hashed password. Alternatively, you can use the
:meth:`~django.contrib.auth.models.UserManager.create_user` helper
method to create a new user with a correctly hashed password.
.. method:: Client.logout()
If your site uses Django's :doc:`authentication system</topics/auth/index>`,
the ``logout()`` method can be used to simulate the effect of a user
logging out of your site.
After you call this method, the test client will have all the cookies
and session data cleared to defaults. Subsequent requests will appear
to come from an :class:`~django.contrib.auth.models.AnonymousUser`.
Testing responses
~~~~~~~~~~~~~~~~~
The ``get()`` and ``post()`` methods both return a ``Response`` object. This
``Response`` object is *not* the same as the ``HttpResponse`` object returned
Django views; the test response object has some additional data useful for
test code to verify.
Specifically, a ``Response`` object has the following attributes:
.. class:: Response()
.. attribute:: client
The test client that was used to make the request that resulted in the
response.
.. attribute:: content
The body of the response, as a string. This is the final page content as
rendered by the view, or any error message.
.. attribute:: context
The template ``Context`` instance that was used to render the template that
produced the response content.
If the rendered page used multiple templates, then ``context`` will be a
list of ``Context`` objects, in the order in which they were rendered.
Regardless of the number of templates used during rendering, you can
retrieve context values using the ``[]`` operator. For example, the
context variable ``name`` could be retrieved using::
>>> response = client.get('/foo/')
>>> response.context['name']
'Arthur'
.. attribute:: request
The request data that stimulated the response.
.. attribute:: status_code
The HTTP status of the response, as an integer. See
:rfc:`2616#section-10` for a full list of HTTP status codes.
.. attribute:: templates
A list of ``Template`` instances used to render the final content, in
the order they were rendered. For each template in the list, use
``template.name`` to get the template's file name, if the template was
loaded from a file. (The name is a string such as
``'admin/index.html'``.)
You can also use dictionary syntax on the response object to query the value
of any settings in the HTTP headers. For example, you could determine the
content type of a response using ``response['Content-Type']``.
Exceptions
~~~~~~~~~~
If you point the test client at a view that raises an exception, that exception
will be visible in the test case. You can then use a standard ``try ... except``
block or :meth:`~unittest.TestCase.assertRaises` to test for exceptions.
The only exceptions that are not visible to the test client are ``Http404``,
``PermissionDenied`` and ``SystemExit``. Django catches these exceptions
internally and converts them into the appropriate HTTP response codes. In these
cases, you can check ``response.status_code`` in your test.
Persistent state
~~~~~~~~~~~~~~~~
The test client is stateful. If a response returns a cookie, then that cookie
will be stored in the test client and sent with all subsequent ``get()`` and
``post()`` requests.
Expiration policies for these cookies are not followed. If you want a cookie
to expire, either delete it manually or create a new ``Client`` instance (which
will effectively delete all cookies).
A test client has two attributes that store persistent state information. You
can access these properties as part of a test condition.
.. attribute:: Client.cookies
A Python :class:`~Cookie.SimpleCookie` object, containing the current values
of all the client cookies. See the documentation of the :mod:`Cookie` module
for more.
.. attribute:: Client.session
A dictionary-like object containing session information. See the
:doc:`session documentation</topics/http/sessions>` for full details.
To modify the session and then save it, it must be stored in a variable
first (because a new ``SessionStore`` is created every time this property
is accessed)::
def test_something(self):
session = self.client.session
session['somekey'] = 'test'
session.save()
Example
~~~~~~~
The following is a simple unit test using the test client::
import unittest
from django.test import Client
class SimpleTest(unittest.TestCase):
def setUp(self):
# Every test needs a client.
self.client = Client()
def test_details(self):
# Issue a GET request.
response = self.client.get('/customer/details/')
# Check that the response is 200 OK.
self.assertEqual(response.status_code, 200)
# Check that the rendered context contains 5 customers.
self.assertEqual(len(response.context['customers']), 5)
.. seealso::
:class:`django.test.RequestFactory`
.. _django-testcase-subclasses:
Provided test case classes
--------------------------
Normal Python unit test classes extend a base class of
:class:`unittest.TestCase`. Django provides a few extensions of this base class:
.. _testcase_hierarchy_diagram:
.. figure:: _images/django_unittest_classes_hierarchy.*
:alt: Hierarchy of Django unit testing classes (TestCase subclasses)
:width: 508
:height: 328
Hierarchy of Django unit testing classes
SimpleTestCase
~~~~~~~~~~~~~~
.. class:: SimpleTestCase()
A thin subclass of :class:`unittest.TestCase`, it extends it with some basic
functionality like:
* Saving and restoring the Python warning machinery state.
* Some useful assertions like:
* Checking that a callable :meth:`raises a certain exception
<SimpleTestCase.assertRaisesMessage>`.
* Testing form field :meth:`rendering and error treatment
<SimpleTestCase.assertFieldOutput>`.
* Testing :meth:`HTML responses for the presence/lack of a given fragment
<SimpleTestCase.assertContains>`.
* Verifying that a template :meth:`has/hasn't been used to generate a given
response content <SimpleTestCase.assertTemplateUsed>`.
* Verifying a HTTP :meth:`redirect <SimpleTestCase.assertRedirects>` is
performed by the app.
* Robustly testing two :meth:`HTML fragments <SimpleTestCase.assertHTMLEqual>`
for equality/inequality or :meth:`containment <SimpleTestCase.assertInHTML>`.
* Robustly testing two :meth:`XML fragments <SimpleTestCase.assertXMLEqual>`
for equality/inequality.
* Robustly testing two :meth:`JSON fragments <SimpleTestCase.assertJSONEqual>`
for equality.
* The ability to run tests with :ref:`modified settings <overriding-settings>`.
* Using the :attr:`~SimpleTestCase.client` :class:`~django.test.Client`.
* Custom test-time :attr:`URL maps <SimpleTestCase.urls>`.
.. versionchanged:: 1.6
The latter two features were moved from ``TransactionTestCase`` to
``SimpleTestCase`` in Django 1.6.
If you need any of the other more complex and heavyweight Django-specific
features like:
* Testing or using the ORM.
* Database :attr:`~TransactionTestCase.fixtures`.
* Test :ref:`skipping based on database backend features <skipping-tests>`.
* The remaining specialized :meth:`assert*
<TransactionTestCase.assertQuerysetEqual>` methods.
then you should use :class:`~django.test.TransactionTestCase` or
:class:`~django.test.TestCase` instead.
``SimpleTestCase`` inherits from ``unittest.TestCase``.
TransactionTestCase
~~~~~~~~~~~~~~~~~~~
.. class:: TransactionTestCase()
Django's ``TestCase`` class (described below) makes use of database transaction
facilities to speed up the process of resetting the database to a known state
at the beginning of each test. A consequence of this, however, is that the
effects of transaction commit and rollback cannot be tested by a Django
``TestCase`` class. If your test requires testing of such transactional
behavior, you should use a Django ``TransactionTestCase``.
``TransactionTestCase`` and ``TestCase`` are identical except for the manner
in which the database is reset to a known state and the ability for test code
to test the effects of commit and rollback:
* A ``TransactionTestCase`` resets the database after the test runs by
truncating all tables. A ``TransactionTestCase`` may call commit and rollback
and observe the effects of these calls on the database.
* A ``TestCase``, on the other hand, does not truncate tables after a test.
Instead, it encloses the test code in a database transaction that is rolled
back at the end of the test. Both explicit commits like
``transaction.commit()`` and implicit ones that may be caused by
``transaction.atomic()`` are replaced with a ``nop`` operation. This
guarantees that the rollback at the end of the test restores the database to
its initial state.
When running on a database that does not support rollback (e.g. MySQL with the
MyISAM storage engine), ``TestCase`` falls back to initializing the database
by truncating tables and reloading initial data.
.. warning::
While ``commit`` and ``rollback`` operations still *appear* to work when
used in ``TestCase``, no actual commit or rollback will be performed by the
database. This can cause your tests to pass or fail unexpectedly. Always
use ``TransactionTestCase`` when testing transactional behavior.
``TransactionTestCase`` inherits from :class:`~django.test.SimpleTestCase`.
TestCase
~~~~~~~~
.. class:: TestCase()
This class provides some additional capabilities that can be useful for testing
Web sites.
Converting a normal :class:`unittest.TestCase` to a Django :class:`TestCase` is
easy: Just change the base class of your test from ``'unittest.TestCase'`` to
``'django.test.TestCase'``. All of the standard Python unit test functionality
will continue to be available, but it will be augmented with some useful
additions, including:
* Automatic loading of fixtures.
* Wraps each test in a transaction.
* Creates a TestClient instance.
* Django-specific assertions for testing for things like redirection and form
errors.
``TestCase`` inherits from :class:`~django.test.TransactionTestCase`.
.. _live-test-server:
LiveServerTestCase
~~~~~~~~~~~~~~~~~~
.. class:: LiveServerTestCase()
``LiveServerTestCase`` does basically the same as
:class:`~django.test.TransactionTestCase` with one extra feature: it launches a
live Django server in the background on setup, and shuts it down on teardown.
This allows the use of automated test clients other than the
:ref:`Django dummy client <test-client>` such as, for example, the Selenium_
client, to execute a series of functional tests inside a browser and simulate a
real user's actions.
By default the live server's address is ``'localhost:8081'`` and the full URL
can be accessed during the tests with ``self.live_server_url``. If you'd like
to change the default address (in the case, for example, where the 8081 port is
already taken) then you may pass a different one to the :djadmin:`test` command
via the :djadminopt:`--liveserver` option, for example:
.. code-block:: bash
./manage.py test --liveserver=localhost:8082
Another way of changing the default server address is by setting the
`DJANGO_LIVE_TEST_SERVER_ADDRESS` environment variable somewhere in your
code (for example, in a :ref:`custom test runner<topics-testing-test_runner>`):
.. code-block:: python
import os
os.environ['DJANGO_LIVE_TEST_SERVER_ADDRESS'] = 'localhost:8082'
In the case where the tests are run by multiple processes in parallel (for
example, in the context of several simultaneous `continuous integration`_
builds), the processes will compete for the same address, and therefore your
tests might randomly fail with an "Address already in use" error. To avoid this
problem, you can pass a comma-separated list of ports or ranges of ports (at
least as many as the number of potential parallel processes). For example:
.. code-block:: bash
./manage.py test --liveserver=localhost:8082,8090-8100,9000-9200,7041
Then, during test execution, each new live test server will try every specified
port until it finds one that is free and takes it.
.. _continuous integration: http://en.wikipedia.org/wiki/Continuous_integration
To demonstrate how to use ``LiveServerTestCase``, let's write a simple Selenium
test. First of all, you need to install the `selenium package`_ into your
Python path:
.. code-block:: bash
pip install selenium
Then, add a ``LiveServerTestCase``-based test to your app's tests module