---
title: "Les tests unitaires"
version: 2.1
locale: fr
source: https://docs.djangoproject.com/fr/2.1/internals/contributing/writing-code/unit-tests/
canonical: https://djangodocs.dev/fr/2.1/internals/contributing/writing-code/unit-tests/
---
# Les tests unitaires

Django est livré avec sa propre suite de tests, dans le répertoire `tests` de la base de code. Notre politique est de nous assurer que tous les tests passent en tout temps.

Nous apprécions toute contribution à la suite de tests !

Les tests de Django utilisent tous l’infrastructure de tests livrée avec Django pour tester les applications. Consultez [Écriture et lancement de tests](/fr/2.1/topics/testing/overview/) pour une explication sur la façon d’écrire de nouveaux tests.

## Lancement des tests unitaires

### Démarrage rapide

Tout d’abord, créez votre [fork de Django sur GitHub](https://github.com/django/django/fork).

Ensuite, créez et activez un environnement virtuel. Si vous n’êtes pas familier avec cette procédure, lisez le [tutoriel de contribution](/fr/2.1/intro/contributing/).

Puis, créez un clone local de votre fork, installez quelques dépendances et lancez la suite de tests

```console
$ git clone git@github.com:YourGitHubName/django.git django-repo
$ cd django-repo/tests
$ pip install -e ..
$ pip install -r requirements/py3.txt
$ ./runtests.py
```

L’installation des dépendances nécessite probablement l’installation de paquets de votre système d’exploitation. Il est généralement possible de savoir quels paquets installer en faisant une recherche Web à propos des dernières lignes du message d’erreur. Essayez d’ajouter le nom de votre système d’exploitation à la requête si nécessaire.

Si vous avez des soucis d’installation des dépendances, vous pouvez omettre cette étape. Voir [Running all the tests](#running-unit-tests-dependencies) pour des détails sur l’installation des dépendances facultatives des tests. Si l’une des dépendances facultatives n’est pas installée, les tests qui l’exigent seront passés (skipped).

Le lancement des tests exige un module de réglages Django définissant la base de données à utiliser. Pour faciliter le démarrage, Django fournit et utilise un module de réglages d’exemple utilisant la base de données SQLite. Voir [Utilisation d’un autre module de réglages settings](#running-unit-tests-settings) pour apprendre comment utiliser un module de réglages différent pour lancer les tests avec une autre base de données.

> **Utilisateurs de Windows**
>
> Nous recommandons quelque chose comme [Git Bash](https://msysgit.github.io/) pour lancer les tests en utilisant l’approche ci-dessus.

Des problèmes ? Voir [Dépannage](#troubleshooting-unit-tests) pour certaines problématiques courantes.

### Lancement des tests avec `tox`

[Tox](https://tox.readthedocs.io/) is a tool for running tests in different
virtual environments. Django includes a basic `tox.ini` that automates some
checks that our build server performs on pull requests. To run the unit tests
and other checks (such as [import sorting](/fr/2.1/internals/contributing/writing-code/coding-style/#coding-style-imports), the
[documentation spelling checker](/fr/2.1/internals/contributing/writing-documentation/#documentation-spelling-check), and
[code formatting](/fr/2.1/internals/contributing/writing-code/coding-style/#coding-style-python)), install and run the `tox`
command from any place in the Django source tree:

```console
$ pip install tox
$ tox
```

By default, `tox` runs the test suite with the bundled test settings file for
SQLite, `flake8`, `isort`, and the documentation spelling checker. In
addition to the system dependencies noted elsewhere in this documentation,
the command `python3` must be on your path and linked to the appropriate
version of Python. A list of default environments can be seen as follows:

```console
$ tox -l
py3
flake8
docs
isort
```

#### Testing other Python versions and database backends

In addition to the default environments, `tox` supports running unit tests
for other versions of Python and other database backends. Since Django’s test
suite doesn’t bundle a settings file for database backends other than SQLite,
however, you must [create and provide your own test settings](#running-unit-tests-settings). For example, to run the tests on Python 3.5
using PostgreSQL:

```console
$ tox -e py35-postgres -- --settings=my_postgres_settings
```

This command sets up a Python 3.5 virtual environment, installs Django’s
test suite dependencies (including those for PostgreSQL), and calls
`runtests.py` with the supplied arguments (in this case,
`--settings=my_postgres_settings`).

The remainder of this documentation shows commands for running tests without
`tox`, however, any option passed to `runtests.py` can also be passed to
`tox` by prefixing the argument list with `--`, as above.

Tox also respects the `DJANGO_SETTINGS_MODULE` environment variable, if set.
For example, the following is equivalent to the command above:

```console
$ DJANGO_SETTINGS_MODULE=my_postgres_settings tox -e py35-postgres
```

#### Running the JavaScript tests

Django includes a set of [JavaScript unit tests](/fr/2.1/internals/contributing/writing-code/javascript/#javascript-tests) for
functions in certain contrib apps. The JavaScript tests aren’t run by default
using `tox` because they require Node.js to be installed and aren’t
necessary for the majority of patches. To run the JavaScript tests using
`tox`:

```console
$ tox -e javascript
```

This command runs `npm install` to ensure test requirements are up to
date and then runs `npm test`.

### Utilisation d’un autre module de réglages `settings`

Le module de réglages inclus (`tests/test_sqlite.py`) permet de lancer la suite de tests avec SQLite. Si vous souhaitez lancer les tests avec une autre base de données, vous devez définir votre propre fichier de réglages. Certains tests, comme ceux de `contrib.postgres`, sont spécifique à un moteur de base de données spécifique et seront omis quand une autre base de données est utilisée.

Pour lancer les tests avec des réglages différents, assurez-vous que le module se trouve dans le chemin `PYTHONPATH` et indiquez ce module avec `--settings`.

Le réglage [`DATABASES`](/fr/2.1/ref/settings/#std-setting-DATABASES) dans tout module de réglages pour les tests doit définir deux bases de données :

- Une base de données `default`. Celle-ci doit utiliser le moteur que vous souhaitez tester de manière principale.
- Une base de données avec l’alias `other`. Celle-ci est utilisée pour tester les requêtes qui sont dirigées vers d’autres bases de données. Elle devrait utiliser le même moteur que la base de données `default`, mais elle doit avoir un autre nom.

Si vous utilisez un moteur autre que SQLite, il est nécessaire de fournir d’autres détails pour chaque base de données :

- L’option [`USER`](/fr/2.1/ref/settings/#std-setting-USER) doit indiquer un compte utilisateur existant pour la base de données. Cet utilisateur a besoin de la permission d’exécuter `CREATE DATABASE` afin de pouvoir créer la base de données de test.
- L’option [`PASSWORD`](/fr/2.1/ref/settings/#std-setting-PASSWORD) doit indiquer le mot de passe à utiliser pour l’utilisateur [`USER`](/fr/2.1/ref/settings/#std-setting-USER).

Test databases get their names by prepending `test_` to the value of the
[`NAME`](/fr/2.1/ref/settings/#std-setting-NAME) settings for the databases defined in [`DATABASES`](/fr/2.1/ref/settings/#std-setting-DATABASES).
These test databases are deleted when the tests are finished.

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 [`CHARSET`](/fr/2.1/ref/settings/#std-setting-TEST_CHARSET) in the
test 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:

```console
$ ./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.

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:

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

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

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

### Running the Selenium tests

Some tests require Selenium and a Web browser. To run these tests, you must
install the [selenium](https://pypi.org/project/selenium/) package and run the tests with the
`--selenium=<BROWSERS>` option. For example, if you have Firefox and Google
Chrome installed:

```console
$ ./runtests.py --selenium=firefox,chrome
```

See the [selenium.webdriver](https://github.com/SeleniumHQ/selenium/tree/master/py/selenium/webdriver) package for the list of available browsers.

Specifying `--selenium` automatically sets `--tags=selenium` to run only
the tests that require selenium.

### Running all the tests

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

- [argon2-cffi](https://pypi.org/project/argon2_cffi/) 16.1.0+
- [bcrypt](https://pypi.org/project/bcrypt/)
- [docutils](https://pypi.org/project/docutils/)
- [geoip2](https://pypi.org/project/geoip2/)
- [jinja2](https://pypi.org/project/jinja2/) 2.7+
- [numpy](https://pypi.org/project/numpy/)
- [Pillow](https://pypi.org/project/Pillow/)
- [PyYAML](https://pyyaml.org/wiki/PyYAML)
- [pytz](https://pypi.org/project/pytz/) (required)
- [setuptools](https://pypi.org/project/setuptools/)
- [memcached](https://memcached.org/), plus a [supported Python binding](/fr/2.1/topics/cache/#memcached)
- [gettext](https://www.gnu.org/software/gettext/manual/gettext.html) ([gettext et Windows](/fr/2.1/topics/i18n/translation/#gettext-on-windows))
- [selenium](https://pypi.org/project/selenium/)
- [sqlparse](https://pypi.org/project/sqlparse/)

You can find these dependencies in [pip requirements files](https://pip.pypa.io/en/latest/user_guide/#requirements-files) inside the
`tests/requirements` directory of the Django source tree and install them
like so:

```console
$ pip install -r tests/requirements/py3.txt
```

Si vous rencontrez une erreur durant l’installation, il est possible qu’une dépendance pour un ou plusieurs paquets Python manque sur votre système. Consultez la documentation du paquet problématique ou recherchez sur le Web avec le message d’erreur obtenu.

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 [`CACHES`](/fr/2.1/ref/settings/#std-setting-CACHES) setting that points at your memcached instance.

To run the GeoDjango tests, you will need to [setup a spatial database
and install the Geospatial libraries](/fr/2.1/ref/contrib/gis/install/).

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

### La couverture de code

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 [testing code coverage](/fr/2.1/topics/testing/advanced/#topics-testing-code-coverage).

Coverage should be run in a single process to obtain accurate statistics. To
run coverage on the Django test suite using the standard test settings:

```console
$ coverage run ./runtests.py --settings=test_sqlite --parallel=1
```

After running coverage, generate the html report by running:

```console
$ 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

Les tests des applications contribuées se trouvent dans le répertoire `tests/`, typiquement sous `<nom_app>_tests`. Par exemple, les tests de `contrib.auth` se trouvent dans `tests/auth_tests`.

## Dépannage

### Nombreux échecs de tests avec `UnicodeEncodeError`

Si le paquet `locales` n’est pas installé, certains tests échoueront avec une exception `UnicodeEncodeError`.

Il est possible de corriger cela par exemple sur les systèmes basés sur Debian en lançant

```console
$ apt-get install locales
$ dpkg-reconfigure locales
```

Il est possible de corriger cela sur les systèmes macOS en configurant la locale du shell

```console
$ export LANG="en_US.UTF-8"
$ export LC_ALL="en_US.UTF-8"
```

Lancez la commande `locale` pour confirmer la modification. Une autre possibilité est d’ajouter ces commandes d’exportation au fichier de démarrage du shell (par ex. `~/.bashrc` pour Bash) afin d’éviter de devoir les retaper.

### Tests that only fail in combination

In case a test passes when run in isolation but fails within the whole suite,
we have some tools to help analyze the problem.

The `--bisect` option of `runtests.py` will run the failing test while
halving the test set it is run together with on each iteration, often making
it possible to identify a small number of tests that may be related to the
failure.

For example, suppose that the failing test that works on its own is
`ModelTest.test_eq`, then using:

```console
$ ./runtests.py --bisect basic.tests.ModelTest.test_eq
```

will try to determine a test that interferes with the given one. First, the
test is run with the first half of the test suite. If a failure occurs, the
first half of the test suite is split in two groups and each group is then run
with the specified test. If there is no failure with the first half of the test
suite, the second half of the test suite is run with the specified test and
split appropriately as described earlier. The process repeats until the set of
failing tests is minimized.

The `--pair` option runs the given test alongside every other test from the
suite, letting you check if another test has side-effects that cause the
failure. So:

```console
$ ./runtests.py --pair basic.tests.ModelTest.test_eq
```

will pair `test_eq` with every test label.

With both `--bisect` and `--pair`, if you already suspect which cases
might be responsible for the failure, you may limit tests to be cross-analyzed
by [specifying further test labels](#runtests-specifying-labels) after
the first one:

```console
$ ./runtests.py --pair basic.tests.ModelTest.test_eq queries transactions
```

You can also try running any set of tests in reverse using the `--reverse`
option in order to verify that executing tests in a different order does not
cause any trouble:

```console
$ ./runtests.py basic --reverse
```

### Seeing the SQL queries run during a test

If you wish to examine the SQL being run in failing tests, you can turn on
[SQL logging](/fr/2.1/topics/logging/#django-db-logger) using the `--debug-sql` option. If you
combine this with `--verbosity=2`, all SQL queries will be output:

```console
$ ./runtests.py basic --debug-sql
```

### Seeing the full traceback of a test failure

By default tests are run in parallel with one process per core. When the tests
are run in parallel, however, you’ll only see a truncated traceback for any
test failures. You can adjust this behavior with the `--parallel` option:

```console
$ ./runtests.py basic --parallel=1
```

You can also use the `DJANGO_TEST_PROCESSES` environment variable for this
purpose.

### Tips for writing tests

#### Isolating model registration

To avoid polluting the global [`apps`](/fr/2.1/ref/applications/#django.apps.apps) registry and prevent
unnecessary table creation, models defined in a test method should be bound to
a temporary `Apps` instance:

```python
from django.apps.registry import Apps
from django.db import models
from django.test import SimpleTestCase

class TestModelDefinition(SimpleTestCase):
    def test_model_definition(self):
        test_apps = Apps(['app_label'])

        class TestModel(models.Model):
            class Meta:
                apps = test_apps
        ...
```

#### `django.test.utils.isolate_apps(*app_labels, attr_name=None, kwarg_name=None)`

Since this pattern involves a lot of boilerplate, Django provides the
[`isolate_apps()`](#django.test.utils.isolate_apps) decorator. It’s used like this:

```python
from django.db import models
from django.test import SimpleTestCase
from django.test.utils import isolate_apps

class TestModelDefinition(SimpleTestCase):
    @isolate_apps('app_label')
    def test_model_definition(self):
        class TestModel(models.Model):
            pass
        ...
```

> **Setting app_label**
>
> Models defined in a test method with no explicit
> [`app_label`](/fr/2.1/ref/models/options/#django.db.models.Options.app_label) are automatically assigned the
> label of the app in which their test class is located.
>
> In order to make sure the models defined within the context of
> [`isolate_apps()`](#django.test.utils.isolate_apps) instances are correctly
> installed, you should pass the set of targeted `app_label` as arguments:
>
> *tests/app\_label/tests.py*
>
> ```python
> from django.db import models
> from django.test import SimpleTestCase
> from django.test.utils import isolate_apps
>
> class TestModelDefinition(SimpleTestCase):
>     @isolate_apps('app_label', 'other_app_label')
>     def test_model_definition(self):
>         # This model automatically receives app_label='app_label'
>         class TestModel(models.Model):
>             pass
>
>         class OtherAppModel(models.Model):
>             class Meta:
>                 app_label = 'other_app_label'
>         ...
> ```

The decorator can also be applied to classes:

```python
from django.db import models
from django.test import SimpleTestCase
from django.test.utils import isolate_apps

@isolate_apps('app_label')
class TestModelDefinition(SimpleTestCase):
    def test_model_definition(self):
        class TestModel(models.Model):
            pass
        ...
```

The temporary `Apps` instance used to isolate model registration can be
retrieved as an attribute when used as a class decorator by using the
`attr_name` parameter:

```python
from django.db import models
from django.test import SimpleTestCase
from django.test.utils import isolate_apps

@isolate_apps('app_label', attr_name='apps')
class TestModelDefinition(SimpleTestCase):
    def test_model_definition(self):
        class TestModel(models.Model):
            pass
        self.assertIs(self.apps.get_model('app_label', 'TestModel'), TestModel)
```

Or as an argument on the test method when used as a method decorator by using
the `kwarg_name` parameter:

```python
from django.db import models
from django.test import SimpleTestCase
from django.test.utils import isolate_apps

class TestModelDefinition(SimpleTestCase):
    @isolate_apps('app_label', kwarg_name='apps')
    def test_model_definition(self, apps):
        class TestModel(models.Model):
            pass
        self.assertIs(apps.get_model('app_label', 'TestModel'), TestModel)
```