django/docs/internals/contributing/writing-code/unit-tests.txt

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==========
Unit tests
==========
Django comes with a test suite of its own, in the ``tests`` directory of the
code base. It's our policy to make sure all tests pass at all times.
The tests cover:
* Models and the database API (``tests/modeltests``),
* Everything else in core Django code (``tests/regressiontests``),
* :ref:`contrib-apps` (``django/contrib/<app>/tests``).
We appreciate any and all contributions to the test suite!
The Django tests all use the testing infrastructure that ships with Django for
testing applications. See :doc:`Testing Django applications </topics/testing>`
for an explanation of how to write new tests.
.. _running-unit-tests:
Running the unit tests
----------------------
Quickstart
~~~~~~~~~~
Running the tests requires a Django settings module that defines the
databases to use. To make it easy to get started, Django provides a
sample settings module that uses the SQLite database. To run the tests
with this sample ``settings`` module, ``cd`` into the Django
``tests/`` directory and run:
.. code-block:: bash
./runtests.py --settings=test_sqlite
If you get an ``ImportError: No module named django.contrib`` error,
you need to add your install of Django to your ``PYTHONPATH``. For
more details on how to do this, read
:ref:`pointing-python-at-the-new-django-version`.
Using another ``settings`` module
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The included settings module allows you to run the test suite using
SQLite. If you want to test behavior using a different database (and
if you're proposing patches for Django, it's a good idea to test
across databases), you may need to define your own settings file.
To run the tests with different settings, ``cd`` to the ``tests/`` directory
and type:
.. code-block:: bash
./runtests.py --settings=path.to.django.settings
The :setting:`DATABASES` setting in this test settings module needs to define
two databases:
* A ``default`` database. This database should use the backend that
you want to use for primary testing
* A database with the alias ``other``. The ``other`` database is
used to establish that queries can be directed to different
databases. As a result, this database can use any backend you
want. It doesn't need to use the same backend as the ``default``
database (although it can use the same backend if you want to).
If you're using a backend that isn't SQLite, you will need to provide other
details for each database:
* The :setting:`USER` option for each of your databases needs to
specify an existing user account for the database.
* The :setting:`PASSWORD` option needs to provide the password for
the :setting:`USER` that has been specified.
* The :setting:`NAME` option must be the name of an existing database to
which the given user has permission to connect. The unit tests will not
touch this database; the test runner creates a new database whose name
is :setting:`NAME` prefixed with ``test_``, and this test database is
deleted when the tests are finished. This means your user account needs
permission to execute ``CREATE DATABASE``.
You will also need to ensure that your database uses UTF-8 as the default
character set. If your database server doesn't use UTF-8 as a default charset,
you will need to include a value for :setting:`TEST_CHARSET` in the settings
dictionary for the applicable database.
Running only some of the tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Django's entire test suite takes a while to run, and running every single test
could be redundant if, say, you just added a test to Django that you want to
run quickly without running everything else. You can run a subset of the unit
tests by appending the names of the test modules to ``runtests.py`` on the
command line.
For example, if you'd like to run tests only for generic relations and
internationalization, type:
.. code-block:: bash
./runtests.py --settings=path.to.settings generic_relations i18n
How do you find out the names of individual tests? Look in
``tests/modeltests`` and ``tests/regressiontests`` — each directory name
there is the name of a test. Contrib app names are also valid test names.
If you just want to run a particular class of tests, you can specify a list of
paths to individual test classes. For example, to run the ``TranslationTests``
of the ``i18n`` module, type:
.. code-block:: bash
./runtests.py --settings=path.to.settings i18n.TranslationTests
Going beyond that, you can specify an individual test method like this:
.. code-block:: bash
./runtests.py --settings=path.to.settings i18n.TranslationTests.test_lazy_objects
Running all the tests
~~~~~~~~~~~~~~~~~~~~~
If you want to run the full suite of tests, you'll need to install a number of
dependencies:
* PyYAML_
* Markdown_
* Textile_
* Docutils_
* setuptools_
* memcached_, plus a :ref:`supported Python binding <memcached>`
* gettext_ (:ref:`gettext_on_windows`)
If you want to test the memcached cache backend, you'll also need to define
a :setting:`CACHES` setting that points at your memcached instance.
Each of these dependencies is optional. If you're missing any of them, the
associated tests will be skipped.
.. _PyYAML: http://pyyaml.org/wiki/PyYAML
.. _Markdown: http://pypi.python.org/pypi/Markdown/1.7
.. _Textile: http://pypi.python.org/pypi/textile
.. _docutils: http://pypi.python.org/pypi/docutils/0.4
.. _setuptools: http://pypi.python.org/pypi/setuptools/
.. _memcached: http://www.danga.com/memcached/
.. _gettext: http://www.gnu.org/software/gettext/manual/gettext.html
.. _contrib-apps:
Contrib apps
------------
Tests for contrib apps go in their respective directories under
``django/contrib``, in a ``tests.py`` file. You can split the tests over
multiple modules by using a ``tests`` directory in the normal Python way.
For the tests to be found, a ``models.py`` file must exist, even if it's empty.
If you have URLs that need to be mapped, put them in ``tests/urls.py``.
To run tests for just one contrib app (e.g. ``markup``), use the same
method as above::
./runtests.py --settings=settings markup