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

==========
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, the database API and everything else in core Django core (``tests/``),
* :ref:`contrib-apps` (``django/contrib/<app>/tests`` or ``tests/<app>_...``).

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:`/topics/testing/overview` 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 and uses a
sample settings module that uses the SQLite database. To run the tests:

.. code-block:: bash

   $ git clone git@github.com:django/django.git django-repo
   $ cd django-repo/tests
   $ PYTHONPATH=..:$PYTHONPATH ./runtests.py

.. versionchanged:: 1.7

Older versions of Django required specifying a settings file:

.. code-block:: bash

   $ PYTHONPATH=..:$PYTHONPATH python ./runtests.py --settings=test_sqlite

``runtests.py`` now uses ``test_sqlite`` by default if settings aren't provided
through either ``--settings`` or :envvar:`DJANGO_SETTINGS_MODULE`.

You can avoid typing the ``PYTHONPATH`` bit each time by adding your Django
checkout to your ``PYTHONPATH`` or by installing the source checkout using pip.
See :ref:`installing-development-version`.

Having problems? See :ref:`troubleshooting-unit-tests` for some common issues.

.. _running-unit-tests-settings:

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, ensure that the module is on your
``PYTHONPATH`` and pass the module with ``--settings``.

The :setting:`DATABASES` setting in any 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). It cannot be the same database as the ``default``.

If you're using a backend that isn't SQLite, you will need to provide other
details for each database:

* The :setting:`USER` option needs to specify an existing user account
  for the database. That user needs permission to execute ``CREATE DATABASE``
  so that the test database can be created.

* The :setting:`PASSWORD` option needs to provide the password for
  the :setting:`USER` that has been specified.

Test databases get their names by prepending ``test_`` to the value of the
:setting:`NAME` settings for the databases defined in :setting:`DATABASES`.
These test databases are deleted when the tests are finished.

.. versionchanged:: 1.7

    Before Django 1.7, the :setting:`NAME` setting was mandatory and had to
    be the name of an existing database to which the given user had permission
    to connect.

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/`` — 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.tests.TranslationTests

Going beyond that, you can specify an individual test method like this:

.. code-block:: bash

   $ ./runtests.py --settings=path.to.settings i18n.tests.TranslationTests.test_lazy_objects

Running the Selenium tests
~~~~~~~~~~~~~~~~~~~~~~~~~~

Some admin tests require Selenium 2, Firefox and Python >= 2.6 to work via a
real Web browser. To allow those tests to run and not be skipped, you must
install the selenium_ package (version > 2.13) into your Python path and run
the tests with the ``--selenium`` option:

.. code-block:: bash

   $ ./runtests.py --settings=test_sqlite --selenium admin_inlines


.. _running-unit-tests-dependencies:

Running all the tests
~~~~~~~~~~~~~~~~~~~~~

If you want to run the full suite of tests, you'll need to install a number of
dependencies:

*  bcrypt_
*  docutils_
*  numpy_
*  Pillow_
*  PyYAML_
*  pytz_
*  setuptools_
*  memcached_, plus a :ref:`supported Python binding <memcached>`
*  gettext_ (:ref:`gettext_on_windows`)
*  selenium_

You can find these dependencies in `pip requirements files`_ inside the
``tests/requirements`` directory of the Django source tree and install them
like so:

.. code-block:: bash

   $ pip install -r tests/requirements/py2.txt  # Python 3: py3.txt

You can also install the database adapter(s) of your choice using
``oracle.txt``, ``mysql.txt``, or ``postgres.txt``.

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.

To run the GeoDjango tests, you will need to :doc:`setup a spatial database
and install the Geospatial libraries</ref/contrib/gis/install/index>`.

Each of these dependencies is optional. If you're missing any of them, the
associated tests will be skipped.

.. _bcrypt: https://pypi.python.org/pypi/bcrypt
.. _docutils: https://pypi.python.org/pypi/docutils
.. _numpy: https://pypi.python.org/pypi/numpy
.. _Pillow: https://pypi.python.org/pypi/Pillow/
.. _PyYAML: http://pyyaml.org/wiki/PyYAML
.. _pytz: https://pypi.python.org/pypi/pytz/
.. _setuptools: https://pypi.python.org/pypi/setuptools/
.. _memcached: http://memcached.org/
.. _gettext: http://www.gnu.org/software/gettext/manual/gettext.html
.. _selenium: https://pypi.python.org/pypi/selenium
.. _pip requirements files: http://www.pip-installer.org/en/latest/cookbook.html#requirements-files

Code coverage
~~~~~~~~~~~~~

Contributors are encouraged to run coverage on the test suite to identify areas
that need additional tests. The coverage tool installation and use is described
in :ref:`testing code coverage<topics-testing-code-coverage>`.

To run coverage on the Django test suite using the standard test settings:

.. code-block:: bash

   $ coverage run ./runtests.py --settings=test_sqlite

After running coverage, generate the html report by running:

.. code-block:: bash

   $ coverage html

When running coverage for the Django tests, the included ``.coveragerc``
settings file  defines ``coverage_html`` as the output directory for the report
and also excludes several directories not relevant to the results
(test code or external code included in Django).

.. _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.

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. ``auth``), use the same
method as above:

.. code-block:: bash

   $ ./runtests.py --settings=settings django.contrib.auth

.. _troubleshooting-unit-tests:

Troubleshooting
---------------

Many test failures with ``UnicodeEncodeError``.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If the ``locales`` package is not installed, some tests will fail with a
``UnicodeEncodeError``.

You can resolve this on Debian-based systems, for example, by running:

.. code-block:: bash

    $ apt-get install locales
    $ dpkg-reconfigure locales