Kaydet (Commit) d19109fd authored tarafından Ramiro Morales's avatar Ramiro Morales

Fixed #19497 -- Refactored testing docs.

Thanks Tim Graham for the review and suggestions.
üst 52a2588d
......@@ -180,7 +180,11 @@ testing of Django applications:
:doc:`Overview <ref/django-admin>` |
:doc:`Adding custom commands <howto/custom-management-commands>`
* **Testing:** :doc:`Overview <topics/testing>`
* **Testing:**
:doc:`Overview <topics/testing/index>` |
:doc:`Writing and running tests <topics/testing/overview>` |
:doc:`Advanced topics <topics/testing/advanced>` |
:doc:`Doctests <topics/testing/doctests>`
* **Deployment:**
:doc:`Overview <howto/deployment/index>` |
......
......@@ -15,8 +15,8 @@ The tests cover:
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.
testing applications. See :doc:`Testing Django applications
</topics/testing/overview>` for an explanation of how to write new tests.
.. _running-unit-tests:
......
......@@ -281,7 +281,7 @@ correctly in a couple different situations.
computer programming, so there's lots of information out there:
* A good first look at writing tests for Django can be found in the
documentation on :doc:`Testing Django applications</topics/testing/>`.
documentation on :doc:`Testing Django applications </topics/testing/overview>`.
* Dive Into Python (a free online book for beginning Python developers)
includes a great `introduction to Unit Testing`__.
* After reading those, if you want something a little meatier to sink
......
......@@ -632,7 +632,7 @@ a piece of code, it usually means that code should be refactored or removed.
Coverage will help to identify dead code. See
:ref:`topics-testing-code-coverage` for details.
:doc:`Testing Django applications </topics/testing>` has comprehensive
:doc:`Testing Django applications </topics/testing/index>` has comprehensive
information about testing.
.. _Selenium: http://seleniumhq.org/
......
......@@ -71,7 +71,7 @@ of 1.0. This includes these APIs:
external template tags. Before adding any such tags, we'll ensure that
Django raises an error if it tries to load tags with duplicate names.
- :doc:`Testing </topics/testing>`
- :doc:`Testing </topics/testing/index>`
- :doc:`django-admin utility </ref/django-admin>`.
......
......@@ -1036,7 +1036,7 @@ test <app or test identifier>
.. django-admin:: test
Runs tests for all installed models. See :doc:`/topics/testing` for more
Runs tests for all installed models. See :doc:`/topics/testing/index` for more
information.
.. django-admin-option:: --failfast
......@@ -1072,7 +1072,7 @@ For example, this command::
...would perform the following steps:
1. Create a test database, as described in :doc:`/topics/testing`.
1. Create a test database, as described in :ref:`the-test-database`.
2. Populate the test database with fixture data from the given fixtures.
(For more on fixtures, see the documentation for ``loaddata`` above.)
3. Runs the Django development server (as in ``runserver``), pointed at
......@@ -1080,7 +1080,7 @@ For example, this command::
This is useful in a number of ways:
* When you're writing :doc:`unit tests </topics/testing>` of how your views
* When you're writing :doc:`unit tests </topics/testing/overview>` of how your views
act with certain fixture data, you can use ``testserver`` to interact with
the views in a Web browser, manually.
......
......@@ -562,7 +562,7 @@ If the default value (``None``) is used with the SQLite database engine, the
tests will use a memory resident database. For all other database engines the
test database will use the name ``'test_' + DATABASE_NAME``.
See :doc:`/topics/testing`.
See :ref:`the-test-database`.
.. setting:: TEST_CREATE
......@@ -1982,9 +1982,7 @@ TEST_RUNNER
Default: ``'django.test.simple.DjangoTestSuiteRunner'``
The name of the class to use for starting the test suite. See
:doc:`/topics/testing`.
.. _Testing Django Applications: ../testing/
:ref:`other-testing-frameworks`.
.. setting:: THOUSAND_SEPARATOR
......
......@@ -476,7 +476,7 @@ Test signals
.. module:: django.test.signals
:synopsis: Signals sent during testing.
Signals only sent when :doc:`running tests </topics/testing>`.
Signals only sent when :ref:`running tests <running-tests>`.
setting_changed
---------------
......
......@@ -220,7 +220,7 @@ supported :doc:`serialization formats </topics/serialization>`, that will be
loaded into your database at the start of your tests. This makes testing with
real data much easier.
See :doc:`the testing documentation </topics/testing>` for the full details.
See :doc:`the testing documentation </topics/testing/index>` for the full details.
Improvements to the admin interface
-----------------------------------
......
......@@ -51,7 +51,7 @@ Performance improvements
.. currentmodule:: django.test
Tests written using Django's :doc:`testing framework </topics/testing>` now run
Tests written using Django's :doc:`testing framework </topics/testing/index>` now run
dramatically faster (as much as 10 times faster in many cases).
This was accomplished through the introduction of transaction-based tests: when
......
......@@ -102,7 +102,7 @@ Testing improvements
.. currentmodule:: django.test.client
A couple of small but very useful improvements have been made to the
:doc:`testing framework </topics/testing>`:
:doc:`testing framework </topics/testing/index>`:
* The test :class:`Client` now can automatically follow redirects with the
``follow`` argument to :meth:`Client.get` and :meth:`Client.post`. This
......
......@@ -264,14 +264,14 @@ Testing improvements
--------------------
A few notable improvements have been made to the :doc:`testing framework
</topics/testing>`.
</topics/testing/index>`.
Test performance improvements
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. currentmodule:: django.test
Tests written using Django's :doc:`testing framework </topics/testing>` now run
Tests written using Django's :doc:`testing framework </topics/testing/index>` now run
dramatically faster (as much as 10 times faster in many cases).
This was accomplished through the introduction of transaction-based tests: when
......
......@@ -13,7 +13,7 @@ Introductions to all the key parts of Django you'll need to know:
templates
class-based-views/index
files
testing
testing/index
auth
cache
conditional-view-processing
......
......@@ -135,7 +135,7 @@ table once ``syncdb`` has created it. After creating a database user with these
permissions, you'll specify the details in your project's settings file,
see :setting:`DATABASES` for details.
If you're using Django's :doc:`testing framework</topics/testing>` to test
If you're using Django's :doc:`testing framework</topics/testing/index>` to test
database queries, Django will need permission to create a test database.
.. _PostgreSQL: http://www.postgresql.org/
......
=======================
Advanced testing topics
=======================
The request factory
===================
.. module:: django.test.client
.. class:: RequestFactory
The :class:`~django.test.client.RequestFactory` shares the same API as
the test client. However, instead of behaving like a browser, the
RequestFactory provides a way to generate a request instance that can
be used as the first argument to any view. This means you can test a
view function the same way as you would test any other function -- as
a black box, with exactly known inputs, testing for specific outputs.
The API for the :class:`~django.test.client.RequestFactory` is a slightly
restricted subset of the test client API:
* It only has access to the HTTP methods :meth:`~Client.get()`,
:meth:`~Client.post()`, :meth:`~Client.put()`,
:meth:`~Client.delete()`, :meth:`~Client.head()` and
:meth:`~Client.options()`.
* These methods accept all the same arguments *except* for
``follows``. Since this is just a factory for producing
requests, it's up to you to handle the response.
* It does not support middleware. Session and authentication
attributes must be supplied by the test itself if required
for the view to function properly.
Example
-------
The following is a simple unit test using the request factory::
from django.utils import unittest
from django.test.client import RequestFactory
class SimpleTest(unittest.TestCase):
def setUp(self):
# Every test needs access to the request factory.
self.factory = RequestFactory()
def test_details(self):
# Create an instance of a GET request.
request = self.factory.get('/customer/details')
# Test my_view() as if it were deployed at /customer/details
response = my_view(request)
self.assertEqual(response.status_code, 200)
.. _topics-testing-advanced-multidb:
Tests and multiple databases
============================
.. _topics-testing-masterslave:
Testing master/slave configurations
-----------------------------------
If you're testing a multiple database configuration with master/slave
replication, this strategy of creating test databases poses a problem.
When the test databases are created, there won't be any replication,
and as a result, data created on the master won't be seen on the
slave.
To compensate for this, Django allows you to define that a database is
a *test mirror*. Consider the following (simplified) example database
configuration::
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'myproject',
'HOST': 'dbmaster',
# ... plus some other settings
},
'slave': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'myproject',
'HOST': 'dbslave',
'TEST_MIRROR': 'default'
# ... plus some other settings
}
}
In this setup, we have two database servers: ``dbmaster``, described
by the database alias ``default``, and ``dbslave`` described by the
alias ``slave``. As you might expect, ``dbslave`` has been configured
by the database administrator as a read slave of ``dbmaster``, so in
normal activity, any write to ``default`` will appear on ``slave``.
If Django created two independent test databases, this would break any
tests that expected replication to occur. However, the ``slave``
database has been configured as a test mirror (using the
:setting:`TEST_MIRROR` setting), indicating that under testing,
``slave`` should be treated as a mirror of ``default``.
When the test environment is configured, a test version of ``slave``
will *not* be created. Instead the connection to ``slave``
will be redirected to point at ``default``. As a result, writes to
``default`` will appear on ``slave`` -- but because they are actually
the same database, not because there is data replication between the
two databases.
.. _topics-testing-creation-dependencies:
Controlling creation order for test databases
---------------------------------------------
By default, Django will always create the ``default`` database first.
However, no guarantees are made on the creation order of any other
databases in your test setup.
If your database configuration requires a specific creation order, you
can specify the dependencies that exist using the
:setting:`TEST_DEPENDENCIES` setting. Consider the following
(simplified) example database configuration::
DATABASES = {
'default': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds']
},
'diamonds': {
# ... db settings
},
'clubs': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds']
},
'spades': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds','hearts']
},
'hearts': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds','clubs']
}
}
Under this configuration, the ``diamonds`` database will be created first,
as it is the only database alias without dependencies. The ``default`` and
``clubs`` alias will be created next (although the order of creation of this
pair is not guaranteed); then ``hearts``; and finally ``spades``.
If there are any circular dependencies in the
:setting:`TEST_DEPENDENCIES` definition, an ``ImproperlyConfigured``
exception will be raised.
Running tests outside the test runner
=====================================
If you want to run tests outside of ``./manage.py test`` -- for example,
from a shell prompt -- you will need to set up the test
environment first. Django provides a convenience method to do this::
>>> from django.test.utils import setup_test_environment
>>> setup_test_environment()
This convenience method sets up the test database, and puts other
Django features into modes that allow for repeatable testing.
The call to :meth:`~django.test.utils.setup_test_environment` is made
automatically as part of the setup of ``./manage.py test``. You only
need to manually invoke this method if you're not using running your
tests via Django's test runner.
.. _other-testing-frameworks:
Using different testing frameworks
==================================
Clearly, :mod:`doctest` and :mod:`unittest` are not the only Python testing
frameworks. While Django doesn't provide explicit support for alternative
frameworks, it does provide a way to invoke tests constructed for an
alternative framework as if they were normal Django tests.
When you run ``./manage.py test``, Django looks at the :setting:`TEST_RUNNER`
setting to determine what to do. By default, :setting:`TEST_RUNNER` points to
``'django.test.simple.DjangoTestSuiteRunner'``. This class defines the default Django
testing behavior. This behavior involves:
#. Performing global pre-test setup.
#. Looking for unit tests and doctests in the ``models.py`` and
``tests.py`` files in each installed application.
#. Creating the test databases.
#. Running ``syncdb`` to install models and initial data into the test
databases.
#. Running the unit tests and doctests that are found.
#. Destroying the test databases.
#. Performing global post-test teardown.
If you define your own test runner class and point :setting:`TEST_RUNNER` at
that class, Django will execute your test runner whenever you run
``./manage.py test``. In this way, it is possible to use any test framework
that can be executed from Python code, or to modify the Django test execution
process to satisfy whatever testing requirements you may have.
.. _topics-testing-test_runner:
Defining a test runner
----------------------
.. currentmodule:: django.test.simple
A test runner is a class defining a ``run_tests()`` method. Django ships
with a ``DjangoTestSuiteRunner`` class that defines the default Django
testing behavior. This class defines the ``run_tests()`` entry point,
plus a selection of other methods that are used to by ``run_tests()`` to
set up, execute and tear down the test suite.
.. class:: DjangoTestSuiteRunner(verbosity=1, interactive=True, failfast=True, **kwargs)
``verbosity`` determines the amount of notification and debug information
that will be printed to the console; ``0`` is no output, ``1`` is normal
output, and ``2`` is verbose output.
If ``interactive`` is ``True``, the test suite has permission to ask the
user for instructions when the test suite is executed. An example of this
behavior would be asking for permission to delete an existing test
database. If ``interactive`` is ``False``, the test suite must be able to
run without any manual intervention.
If ``failfast`` is ``True``, the test suite will stop running after the
first test failure is detected.
Django will, from time to time, extend the capabilities of
the test runner by adding new arguments. The ``**kwargs`` declaration
allows for this expansion. If you subclass ``DjangoTestSuiteRunner`` or
write your own test runner, ensure accept and handle the ``**kwargs``
parameter.
.. versionadded:: 1.4
Your test runner may also define additional command-line options.
If you add an ``option_list`` attribute to a subclassed test runner,
those options will be added to the list of command-line options that
the :djadmin:`test` command can use.
Attributes
~~~~~~~~~~
.. attribute:: DjangoTestSuiteRunner.option_list
.. versionadded:: 1.4
This is the tuple of ``optparse`` options which will be fed into the
management command's ``OptionParser`` for parsing arguments. See the
documentation for Python's ``optparse`` module for more details.
Methods
~~~~~~~
.. method:: DjangoTestSuiteRunner.run_tests(test_labels, extra_tests=None, **kwargs)
Run the test suite.
``test_labels`` is a list of strings describing the tests to be run. A test
label can take one of three forms:
* ``app.TestCase.test_method`` -- Run a single test method in a test
case.
* ``app.TestCase`` -- Run all the test methods in a test case.
* ``app`` -- Search for and run all tests in the named application.
If ``test_labels`` has a value of ``None``, the test runner should run
search for tests in all the applications in :setting:`INSTALLED_APPS`.
``extra_tests`` is a list of extra ``TestCase`` instances to add to the
suite that is executed by the test runner. These extra tests are run
in addition to those discovered in the modules listed in ``test_labels``.
This method should return the number of tests that failed.
.. method:: DjangoTestSuiteRunner.setup_test_environment(**kwargs)
Sets up the test environment ready for testing.
.. method:: DjangoTestSuiteRunner.build_suite(test_labels, extra_tests=None, **kwargs)
Constructs a test suite that matches the test labels provided.
``test_labels`` is a list of strings describing the tests to be run. A test
label can take one of three forms:
* ``app.TestCase.test_method`` -- Run a single test method in a test
case.
* ``app.TestCase`` -- Run all the test methods in a test case.
* ``app`` -- Search for and run all tests in the named application.
If ``test_labels`` has a value of ``None``, the test runner should run
search for tests in all the applications in :setting:`INSTALLED_APPS`.
``extra_tests`` is a list of extra ``TestCase`` instances to add to the
suite that is executed by the test runner. These extra tests are run
in addition to those discovered in the modules listed in ``test_labels``.
Returns a ``TestSuite`` instance ready to be run.
.. method:: DjangoTestSuiteRunner.setup_databases(**kwargs)
Creates the test databases.
Returns a data structure that provides enough detail to undo the changes
that have been made. This data will be provided to the ``teardown_databases()``
function at the conclusion of testing.
.. method:: DjangoTestSuiteRunner.run_suite(suite, **kwargs)
Runs the test suite.
Returns the result produced by the running the test suite.
.. method:: DjangoTestSuiteRunner.teardown_databases(old_config, **kwargs)
Destroys the test databases, restoring pre-test conditions.
``old_config`` is a data structure defining the changes in the
database configuration that need to be reversed. It is the return
value of the ``setup_databases()`` method.
.. method:: DjangoTestSuiteRunner.teardown_test_environment(**kwargs)
Restores the pre-test environment.
.. method:: DjangoTestSuiteRunner.suite_result(suite, result, **kwargs)
Computes and returns a return code based on a test suite, and the result
from that test suite.
Testing utilities
-----------------
.. module:: django.test.utils
:synopsis: Helpers to write custom test runners.
To assist in the creation of your own test runner, Django provides a number of
utility methods in the ``django.test.utils`` module.
.. function:: setup_test_environment()
Performs any global pre-test setup, such as the installing the
instrumentation of the template rendering system and setting up
the dummy email outbox.
.. function:: teardown_test_environment()
Performs any global post-test teardown, such as removing the black
magic hooks into the template system and restoring normal email
services.
.. currentmodule:: django.db.connection.creation
The creation module of the database backend (``connection.creation``)
also provides some utilities that can be useful during testing.
.. function:: create_test_db([verbosity=1, autoclobber=False])
Creates a new test database and runs ``syncdb`` against it.
``verbosity`` has the same behavior as in ``run_tests()``.
``autoclobber`` describes the behavior that will occur if a
database with the same name as the test database is discovered:
* If ``autoclobber`` is ``False``, the user will be asked to
approve destroying the existing database. ``sys.exit`` is
called if the user does not approve.
* If autoclobber is ``True``, the database will be destroyed
without consulting the user.
Returns the name of the test database that it created.
``create_test_db()`` has the side effect of modifying the value of
:setting:`NAME` in :setting:`DATABASES` to match the name of the test
database.
.. function:: destroy_test_db(old_database_name, [verbosity=1])
Destroys the database whose name is the value of :setting:`NAME` in
:setting:`DATABASES`, and sets :setting:`NAME` to the value of
``old_database_name``.
The ``verbosity`` argument has the same behavior as for
:class:`~django.test.simple.DjangoTestSuiteRunner`.
.. _topics-testing-code-coverage:
Integration with coverage.py
============================
Code coverage describes how much source code has been tested. It shows which
parts of your code are being exercised by tests and which are not. It's an
important part of testing applications, so it's strongly recommended to check
the coverage of your tests.
Django can be easily integrated with `coverage.py`_, a tool for measuring code
coverage of Python programs. First, `install coverage.py`_. Next, run the
following from your project folder containing ``manage.py``::
coverage run --source='.' manage.py test myapp
This runs your tests and collects coverage data of the executed files in your
project. You can see a report of this data by typing following command::
coverage report
Note that some Django code was executed while running tests, but it is not
listed here because of the ``source`` flag passed to the previous command.
For more options like annotated HTML listings detailing missed lines, see the
`coverage.py`_ docs.
.. _coverage.py: http://nedbatchelder.com/code/coverage/
.. _install coverage.py: http://pypi.python.org/pypi/coverage
===================
Django and doctests
===================
Doctests use Python's standard :mod:`doctest` module, which searches your
docstrings for statements that resemble a session of the Python interactive
interpreter. A full explanation of how :mod:`doctest` works is out of the scope
of this document; read Python's official documentation for the details.
.. admonition:: What's a **docstring**?
A good explanation of docstrings (and some guidelines for using them
effectively) can be found in :pep:`257`:
A docstring is a string literal that occurs as the first statement in
a module, function, class, or method definition. Such a docstring
becomes the ``__doc__`` special attribute of that object.
For example, this function has a docstring that describes what it does::
def add_two(num):
"Return the result of adding two to the provided number."
return num + 2
Because tests often make great documentation, putting tests directly in
your docstrings is an effective way to document *and* test your code.
As with unit tests, for a given Django application, the test runner looks for
doctests in two places:
* The ``models.py`` file. You can define module-level doctests and/or a
doctest for individual models. It's common practice to put
application-level doctests in the module docstring and model-level
doctests in the model docstrings.
* A file called ``tests.py`` in the application directory -- i.e., the
directory that holds ``models.py``. This file is a hook for any and all
doctests you want to write that aren't necessarily related to models.
This example doctest is equivalent to the example given in the unittest section
above::
# models.py
from django.db import models
class Animal(models.Model):
"""
An animal that knows how to make noise
# Create some animals
>>> lion = Animal.objects.create(name="lion", sound="roar")
>>> cat = Animal.objects.create(name="cat", sound="meow")
# Make 'em speak
>>> lion.speak()
'The lion says "roar"'
>>> cat.speak()
'The cat says "meow"'
"""
name = models.CharField(max_length=20)
sound = models.CharField(max_length=20)
def speak(self):
return 'The %s says "%s"' % (self.name, self.sound)
When you :ref:`run your tests <running-tests>`, the test runner will find this
docstring, notice that portions of it look like an interactive Python session,
and execute those lines while checking that the results match.
In the case of model tests, note that the test runner takes care of creating
its own test database. That is, any test that accesses a database -- by
creating and saving model instances, for example -- will not affect your
production database. However, the database is not refreshed between doctests,
so if your doctest requires a certain state you should consider flushing the
database or loading a fixture. (See the section on :ref:`fixtures
<topics-testing-fixtures>` for more on this.) Note that to use this feature,
the database user Django is connecting as must have ``CREATE DATABASE``
rights.
For more details about :mod:`doctest`, see the Python documentation.
=================
Testing in Django
=================
.. toctree::
:hidden:
overview
doctests
advanced
Automated testing is an extremely useful bug-killing tool for the modern
Web developer. You can use a collection of tests -- a **test suite** -- to
solve, or avoid, a number of problems:
* When you're writing new code, you can use tests to validate your code
works as expected.
* When you're refactoring or modifying old code, you can use tests to
ensure your changes haven't affected your application's behavior
unexpectedly.
Testing a Web application is a complex task, because a Web application is made
of several layers of logic -- from HTTP-level request handling, to form
validation and processing, to template rendering. With Django's test-execution
framework and assorted utilities, you can simulate requests, insert test data,
inspect your application's output and generally verify your code is doing what
it should be doing.
The best part is, it's really easy.
Unit tests v. doctests
======================
There are two primary ways to write tests with Django, corresponding to the
two test frameworks that ship in the Python standard library. The two
frameworks are:
* **Unit tests** -- tests that are expressed as methods on a Python class
that subclasses :class:`unittest.TestCase` or Django's customized
:class:`TestCase`. For example::
import unittest
class MyFuncTestCase(unittest.TestCase):
def testBasic(self):
a = ['larry', 'curly', 'moe']
self.assertEqual(my_func(a, 0), 'larry')
self.assertEqual(my_func(a, 1), 'curly')
* **Doctests** -- tests that are embedded in your functions' docstrings and
are written in a way that emulates a session of the Python interactive
interpreter. For example::
def my_func(a_list, idx):
"""
>>> a = ['larry', 'curly', 'moe']
>>> my_func(a, 0)
'larry'
>>> my_func(a, 1)
'curly'
"""
return a_list[idx]
Which should I use?
-------------------
Because Django supports both of the standard Python test frameworks, it's up to
you and your tastes to decide which one to use. You can even decide to use
*both*.
For developers new to testing, however, this choice can seem confusing. Here,
then, are a few key differences to help you decide which approach is right for
you:
* If you've been using Python for a while, :mod:`doctest` will probably feel
more "pythonic". It's designed to make writing tests as easy as possible,
so it requires no overhead of writing classes or methods. You simply put
tests in docstrings. This has the added advantage of serving as
documentation (and correct documentation, at that!). However, while
doctests are good for some simple example code, they are not very good if
you want to produce either high quality, comprehensive tests or high
quality documentation. Test failures are often difficult to debug
as it can be unclear exactly why the test failed. Thus, doctests should
generally be avoided and used primarily for documentation examples only.
* The :mod:`unittest` framework will probably feel very familiar to
developers coming from Java. :mod:`unittest` is inspired by Java's JUnit,
so you'll feel at home with this method if you've used JUnit or any test
framework inspired by JUnit.
* If you need to write a bunch of tests that share similar code, then
you'll appreciate the :mod:`unittest` framework's organization around
classes and methods. This makes it easy to abstract common tasks into
common methods. The framework also supports explicit setup and/or cleanup
routines, which give you a high level of control over the environment
in which your test cases are run.
* If you're writing tests for Django itself, you should use :mod:`unittest`.
Where to go from here
=====================
As unit tests are preferred in Django, we treat them in detail in the
:doc:`overview` document.
:doc:`doctests` describes Django-specific features when using doctests.
You can also use any *other* Python test framework, Django provides an API and
tools for that kind of integration. They are described in the
:ref:`other-testing-frameworks` section of :doc:`advanced`.
......@@ -5,69 +5,17 @@ Testing Django applications
.. module:: django.test
:synopsis: Testing tools for Django applications.
Automated testing is an extremely useful bug-killing tool for the modern
Web developer. You can use a collection of tests -- a **test suite** -- to
solve, or avoid, a number of problems:
.. seealso::
* When you're writing new code, you can use tests to validate your code
works as expected.
The :doc:`testing tutorial </intro/tutorial05>` and the
:doc:`advanced testing topics </topics/testing/advanced>`.
* When you're refactoring or modifying old code, you can use tests to
ensure your changes haven't affected your application's behavior
unexpectedly.
Testing a Web application is a complex task, because a Web application is made
of several layers of logic -- from HTTP-level request handling, to form
validation and processing, to template rendering. With Django's test-execution
framework and assorted utilities, you can simulate requests, insert test data,
inspect your application's output and generally verify your code is doing what
it should be doing.
The best part is, it's really easy.
This document is split into two primary sections. First, we explain how to
write tests with Django. Then, we explain how to run them.
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
=============
There are two primary ways to write tests with Django, corresponding to the
two test frameworks that ship in the Python standard library. The two
frameworks are:
* **Unit tests** -- tests that are expressed as methods on a Python class
that subclasses :class:`unittest.TestCase` or Django's customized
:class:`TestCase`. For example::
import unittest
class MyFuncTestCase(unittest.TestCase):
def testBasic(self):
a = ['larry', 'curly', 'moe']
self.assertEqual(my_func(a, 0), 'larry')
self.assertEqual(my_func(a, 1), 'curly')
* **Doctests** -- tests that are embedded in your functions' docstrings and
are written in a way that emulates a session of the Python interactive
interpreter. For example::
def my_func(a_list, idx):
"""
>>> a = ['larry', 'curly', 'moe']
>>> my_func(a, 0)
'larry'
>>> my_func(a, 1)
'curly'
"""
return a_list[idx]
We'll discuss choosing the appropriate test framework later, however, most
experienced developers prefer unit tests. You can also use any *other* Python
test framework, as we'll explain in a bit.
Writing unit tests
------------------
Django's unit tests use a Python standard library module: :mod:`unittest`. This
module defines tests in class-based approach.
......@@ -151,122 +99,6 @@ For more details about :mod:`unittest`, see the Python documentation.
applications the scope of tests you will be able to write this way will
be fairly limited, so it's easiest to use :class:`django.test.TestCase`.
Writing doctests
----------------
Doctests use Python's standard :mod:`doctest` module, which searches your
docstrings for statements that resemble a session of the Python interactive
interpreter. A full explanation of how :mod:`doctest` works is out of the scope
of this document; read Python's official documentation for the details.
.. admonition:: What's a **docstring**?
A good explanation of docstrings (and some guidelines for using them
effectively) can be found in :pep:`257`:
A docstring is a string literal that occurs as the first statement in
a module, function, class, or method definition. Such a docstring
becomes the ``__doc__`` special attribute of that object.
For example, this function has a docstring that describes what it does::
def add_two(num):
"Return the result of adding two to the provided number."
return num + 2
Because tests often make great documentation, putting tests directly in
your docstrings is an effective way to document *and* test your code.
As with unit tests, for a given Django application, the test runner looks for
doctests in two places:
* The ``models.py`` file. You can define module-level doctests and/or a
doctest for individual models. It's common practice to put
application-level doctests in the module docstring and model-level
doctests in the model docstrings.
* A file called ``tests.py`` in the application directory -- i.e., the
directory that holds ``models.py``. This file is a hook for any and all
doctests you want to write that aren't necessarily related to models.
This example doctest is equivalent to the example given in the unittest section
above::
# models.py
from django.db import models
class Animal(models.Model):
"""
An animal that knows how to make noise
# Create some animals
>>> lion = Animal.objects.create(name="lion", sound="roar")
>>> cat = Animal.objects.create(name="cat", sound="meow")
# Make 'em speak
>>> lion.speak()
'The lion says "roar"'
>>> cat.speak()
'The cat says "meow"'
"""
name = models.CharField(max_length=20)
sound = models.CharField(max_length=20)
def speak(self):
return 'The %s says "%s"' % (self.name, self.sound)
When you :ref:`run your tests <running-tests>`, the test runner will find this
docstring, notice that portions of it look like an interactive Python session,
and execute those lines while checking that the results match.
In the case of model tests, note that the test runner takes care of creating
its own test database. That is, any test that accesses a database -- by
creating and saving model instances, for example -- will not affect your
production database. However, the database is not refreshed between doctests,
so if your doctest requires a certain state you should consider flushing the
database or loading a fixture. (See the section on fixtures, below, for more
on this.) Note that to use this feature, the database user Django is connecting
as must have ``CREATE DATABASE`` rights.
For more details about :mod:`doctest`, see the Python documentation.
Which should I use?
-------------------
Because Django supports both of the standard Python test frameworks, it's up to
you and your tastes to decide which one to use. You can even decide to use
*both*.
For developers new to testing, however, this choice can seem confusing. Here,
then, are a few key differences to help you decide which approach is right for
you:
* If you've been using Python for a while, :mod:`doctest` will probably feel
more "pythonic". It's designed to make writing tests as easy as possible,
so it requires no overhead of writing classes or methods. You simply put
tests in docstrings. This has the added advantage of serving as
documentation (and correct documentation, at that!). However, while
doctests are good for some simple example code, they are not very good if
you want to produce either high quality, comprehensive tests or high
quality documentation. Test failures are often difficult to debug
as it can be unclear exactly why the test failed. Thus, doctests should
generally be avoided and used primarily for documentation examples only.
* The :mod:`unittest` framework will probably feel very familiar to
developers coming from Java. :mod:`unittest` is inspired by Java's JUnit,
so you'll feel at home with this method if you've used JUnit or any test
framework inspired by JUnit.
* If you need to write a bunch of tests that share similar code, then
you'll appreciate the :mod:`unittest` framework's organization around
classes and methods. This makes it easy to abstract common tasks into
common methods. The framework also supports explicit setup and/or cleanup
routines, which give you a high level of control over the environment
in which your test cases are run.
* If you're writing tests for Django itself, you should use :mod:`unittest`.
.. _running-tests:
Running tests
......@@ -341,23 +173,7 @@ be reported, and any test databases created by the run will not be destroyed.
flag areas in your code that aren't strictly wrong but could benefit
from a better implementation.
Running tests outside the test runner
-------------------------------------
If you want to run tests outside of ``./manage.py test`` -- for example,
from a shell prompt -- you will need to set up the test
environment first. Django provides a convenience method to do this::
>>> from django.test.utils import setup_test_environment
>>> setup_test_environment()
This convenience method sets up the test database, and puts other
Django features into modes that allow for repeatable testing.
The call to :meth:`~django.test.utils.setup_test_environment` is made
automatically as part of the setup of ``./manage.py test``. You only
need to manually invoke this method if you're not using running your
tests via Django's test runner.
.. _the-test-database:
The test database
-----------------
......@@ -400,100 +216,9 @@ advanced settings.
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.
.. _topics-testing-masterslave:
Testing master/slave configurations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you're testing a multiple database configuration with master/slave
replication, this strategy of creating test databases poses a problem.
When the test databases are created, there won't be any replication,
and as a result, data created on the master won't be seen on the
slave.
To compensate for this, Django allows you to define that a database is
a *test mirror*. Consider the following (simplified) example database
configuration::
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'myproject',
'HOST': 'dbmaster',
# ... plus some other settings
},
'slave': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'myproject',
'HOST': 'dbslave',
'TEST_MIRROR': 'default'
# ... plus some other settings
}
}
In this setup, we have two database servers: ``dbmaster``, described
by the database alias ``default``, and ``dbslave`` described by the
alias ``slave``. As you might expect, ``dbslave`` has been configured
by the database administrator as a read slave of ``dbmaster``, so in
normal activity, any write to ``default`` will appear on ``slave``.
If Django created two independent test databases, this would break any
tests that expected replication to occur. However, the ``slave``
database has been configured as a test mirror (using the
:setting:`TEST_MIRROR` setting), indicating that under testing,
``slave`` should be treated as a mirror of ``default``.
When the test environment is configured, a test version of ``slave``
will *not* be created. Instead the connection to ``slave``
will be redirected to point at ``default``. As a result, writes to
``default`` will appear on ``slave`` -- but because they are actually
the same database, not because there is data replication between the
two databases.
.. _topics-testing-creation-dependencies:
Controlling creation order for test databases
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
By default, Django will always create the ``default`` database first.
However, no guarantees are made on the creation order of any other
databases in your test setup.
If your database configuration requires a specific creation order, you
can specify the dependencies that exist using the
:setting:`TEST_DEPENDENCIES` setting. Consider the following
(simplified) example database configuration::
DATABASES = {
'default': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds']
},
'diamonds': {
# ... db settings
},
'clubs': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds']
},
'spades': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds','hearts']
},
'hearts': {
# ... db settings
'TEST_DEPENDENCIES': ['diamonds','clubs']
}
}
Under this configuration, the ``diamonds`` database will be created first,
as it is the only database alias without dependencies. The ``default`` and
``clubs`` alias will be created next (although the order of creation of this
pair is not guaranteed); then ``hearts``; and finally ``spades``.
If there are any circular dependencies in the
:setting:`TEST_DEPENDENCIES` definition, an ``ImproperlyConfigured``
exception will be raised.
.. seealso::
The :ref:`advanced multi-db testing topics <topics-testing-advanced-multidb>`.
Order in which tests are executed
---------------------------------
......@@ -610,36 +335,6 @@ to a faster hashing algorithm::
Don't forget to also include in :setting:`PASSWORD_HASHERS` any hashing
algorithm used in fixtures, if any.
.. _topics-testing-code-coverage:
Integration with coverage.py
----------------------------
Code coverage describes how much source code has been tested. It shows which
parts of your code are being exercised by tests and which are not. It's an
important part of testing applications, so it's strongly recommended to check
the coverage of your tests.
Django can be easily integrated with `coverage.py`_, a tool for measuring code
coverage of Python programs. First, `install coverage.py`_. Next, run the
following from your project folder containing ``manage.py``::
coverage run --source='.' manage.py test myapp
This runs your tests and collects coverage data of the executed files in your
project. You can see a report of this data by typing following command::
coverage report
Note that some Django code was executed while running tests, but it is not
listed here because of the ``source`` flag passed to the previous command.
For more options like annotated HTML listings detailing missed lines, see the
`coverage.py`_ docs.
.. _coverage.py: http://nedbatchelder.com/code/coverage/
.. _install coverage.py: http://pypi.python.org/pypi/coverage
Testing tools
=============
......@@ -1136,60 +831,12 @@ The following is a simple unit test using the test client::
# Check that the rendered context contains 5 customers.
self.assertEqual(len(response.context['customers']), 5)
The request factory
-------------------
.. class:: RequestFactory
The :class:`~django.test.client.RequestFactory` shares the same API as
the test client. However, instead of behaving like a browser, the
RequestFactory provides a way to generate a request instance that can
be used as the first argument to any view. This means you can test a
view function the same way as you would test any other function -- as
a black box, with exactly known inputs, testing for specific outputs.
The API for the :class:`~django.test.client.RequestFactory` is a slightly
restricted subset of the test client API:
* It only has access to the HTTP methods :meth:`~Client.get()`,
:meth:`~Client.post()`, :meth:`~Client.put()`,
:meth:`~Client.delete()`, :meth:`~Client.head()` and
:meth:`~Client.options()`.
* These methods accept all the same arguments *except* for
``follows``. Since this is just a factory for producing
requests, it's up to you to handle the response.
* It does not support middleware. Session and authentication
attributes must be supplied by the test itself if required
for the view to function properly.
Example
~~~~~~~
The following is a simple unit test using the request factory::
from django.utils import unittest
from django.test.client import RequestFactory
class SimpleTest(unittest.TestCase):
def setUp(self):
# Every test needs access to the request factory.
self.factory = RequestFactory()
def test_details(self):
# Create an instance of a GET request.
request = self.factory.get('/customer/details')
# Test my_view() as if it were deployed at /customer/details
response = my_view(request)
self.assertEqual(response.status_code, 200)
.. seealso::
Test cases
----------
:class:`django.test.client.RequestFactory`
Provided test case classes
~~~~~~~~~~~~~~~~~~~~~~~~~~
--------------------------
.. currentmodule:: django.test
......@@ -1208,37 +855,39 @@ Normal Python unit test classes extend a base class of
Regardless of the version of Python you're using, if you've installed
:mod:`unittest2`, :mod:`django.utils.unittest` will point to that library.
TestCase
^^^^^^^^
.. class:: TestCase()
SimpleTestCase
~~~~~~~~~~~~~~
This class provides some additional capabilities that can be useful for testing
Web sites.
.. class:: SimpleTestCase()
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:
.. versionadded:: 1.4
* Automatic loading of fixtures.
A very thin subclass of :class:`unittest.TestCase`, it extends it with some
basic functionality like:
* Wraps each test in a transaction.
* Saving and restoring the Python warning machinery state.
* Checking that a callable :meth:`raises a certain exception <SimpleTestCase.assertRaisesMessage>`.
* :meth:`Testing form field rendering <SimpleTestCase.assertFieldOutput>`.
* Testing server :ref:`HTML responses for the presence/lack of a given fragment <assertions>`.
* The ability to run tests with :ref:`modified settings <overriding-settings>`
* Creates a TestClient instance.
If you need any of the other more complex and heavyweight Django-specific
features like:
* Django-specific assertions for testing for things like redirection and form
errors.
* Using the :attr:`~TestCase.client` :class:`~django.test.client.Client`.
* Testing or using the ORM.
* Database :attr:`~TestCase.fixtures`.
* Custom test-time :attr:`URL maps <TestCase.urls>`.
* Test :ref:`skipping based on database backend features <skipping-tests>`.
* The remaining specialized :ref:`assert* <assertions>` methods.
.. versionchanged:: 1.5
The order in which tests are run has changed. See `Order in which tests are
executed`_.
then you should use :class:`~django.test.TransactionTestCase` or
:class:`~django.test.TestCase` instead.
``TestCase`` inherits from :class:`~django.test.TransactionTestCase`.
``SimpleTestCase`` inherits from :class:`django.utils.unittest.TestCase`.
TransactionTestCase
^^^^^^^^^^^^^^^^^^^
~~~~~~~~~~~~~~~~~~~
.. class:: TransactionTestCase()
......@@ -1309,121 +958,270 @@ to test the effects of commit and rollback:
Using ``reset_sequences = True`` will slow down the test, since the primary
key reset is an relatively expensive database operation.
SimpleTestCase
^^^^^^^^^^^^^^
.. class:: SimpleTestCase()
TestCase
~~~~~~~~
.. versionadded:: 1.4
.. class:: TestCase()
A very thin subclass of :class:`unittest.TestCase`, it extends it with some
basic functionality like:
This class provides some additional capabilities that can be useful for testing
Web sites.
* Saving and restoring the Python warning machinery state.
* Checking that a callable :meth:`raises a certain exception <SimpleTestCase.assertRaisesMessage>`.
* :meth:`Testing form field rendering <SimpleTestCase.assertFieldOutput>`.
* Testing server :ref:`HTML responses for the presence/lack of a given fragment <assertions>`.
* The ability to run tests with :ref:`modified settings <overriding-settings>`
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:
If you need any of the other more complex and heavyweight Django-specific
features like:
* Automatic loading of fixtures.
* Using the :attr:`~TestCase.client` :class:`~django.test.client.Client`.
* Testing or using the ORM.
* Database :attr:`~TestCase.fixtures`.
* Custom test-time :attr:`URL maps <TestCase.urls>`.
* Test :ref:`skipping based on database backend features <skipping-tests>`.
* The remaining specialized :ref:`assert* <assertions>` methods.
* Wraps each test in a transaction.
then you should use :class:`~django.test.TransactionTestCase` or
:class:`~django.test.TestCase` instead.
* Creates a TestClient instance.
``SimpleTestCase`` inherits from :class:`django.utils.unittest.TestCase`.
* Django-specific assertions for testing for things like redirection and form
errors.
Default test client
~~~~~~~~~~~~~~~~~~~
.. versionchanged:: 1.5
The order in which tests are run has changed. See `Order in which tests are
executed`_.
.. attribute:: TestCase.client
``TestCase`` inherits from :class:`~django.test.TransactionTestCase`.
Every test case in a ``django.test.TestCase`` instance has access to an
instance of a Django test client. This client can be accessed as
``self.client``. This client is recreated for each test, so you don't have to
worry about state (such as cookies) carrying over from one test to another.
.. _live-test-server:
This means, instead of instantiating a ``Client`` in each test::
LiveServerTestCase
~~~~~~~~~~~~~~~~~~
from django.utils import unittest
from django.test.client import Client
.. versionadded:: 1.4
class SimpleTest(unittest.TestCase):
def test_details(self):
client = Client()
response = client.get('/customer/details/')
self.assertEqual(response.status_code, 200)
.. class:: LiveServerTestCase()
def test_index(self):
client = Client()
response = client.get('/customer/index/')
self.assertEqual(response.status_code, 200)
``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.
...you can just refer to ``self.client``, like so::
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:
from django.test import TestCase
.. code-block:: bash
class SimpleTest(TestCase):
def test_details(self):
response = self.client.get('/customer/details/')
self.assertEqual(response.status_code, 200)
./manage.py test --liveserver=localhost:8082
def test_index(self):
response = self.client.get('/customer/index/')
self.assertEqual(response.status_code, 200)
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>`):
Customizing the test client
~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: python
.. attribute:: TestCase.client_class
import os
os.environ['DJANGO_LIVE_TEST_SERVER_ADDRESS'] = 'localhost:8082'
If you want to use a different ``Client`` class (for example, a subclass
with customized behavior), use the :attr:`~TestCase.client_class` class
attribute::
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:
from django.test import TestCase
from django.test.client import Client
.. code-block:: bash
class MyTestClient(Client):
# Specialized methods for your environment...
./manage.py test --liveserver=localhost:8082,8090-8100,9000-9200,7041
class MyTest(TestCase):
client_class = MyTestClient
Then, during test execution, each new live test server will try every specified
port until it finds one that is free and takes it.
def test_my_stuff(self):
# Here self.client is an instance of MyTestClient...
call_some_test_code()
.. _continuous integration: http://en.wikipedia.org/wiki/Continuous_integration
.. _topics-testing-fixtures:
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:
Fixture loading
~~~~~~~~~~~~~~~
.. code-block:: bash
.. attribute:: TestCase.fixtures
pip install selenium
A test case for a database-backed Web site isn't much use if there isn't any
data in the database. To make it easy to put test data into the database,
Django's custom ``TestCase`` class provides a way of loading **fixtures**.
Then, add a ``LiveServerTestCase``-based test to your app's tests module
(for example: ``myapp/tests.py``). The code for this test may look as follows:
A fixture is a collection of data that Django knows how to import into a
database. For example, if your site has user accounts, you might set up a
fixture of fake user accounts in order to populate your database during tests.
.. code-block:: python
The most straightforward way of creating a fixture is to use the
:djadmin:`manage.py dumpdata <dumpdata>` command. This assumes you
already have some data in your database. See the :djadmin:`dumpdata
documentation<dumpdata>` for more details.
from django.test import LiveServerTestCase
from selenium.webdriver.firefox.webdriver import WebDriver
.. note::
class MySeleniumTests(LiveServerTestCase):
fixtures = ['user-data.json']
If you've ever run :djadmin:`manage.py syncdb<syncdb>`, you've
@classmethod
def setUpClass(cls):
cls.selenium = WebDriver()
super(MySeleniumTests, cls).setUpClass()
@classmethod
def tearDownClass(cls):
cls.selenium.quit()
super(MySeleniumTests, cls).tearDownClass()
def test_login(self):
self.selenium.get('%s%s' % (self.live_server_url, '/login/'))
username_input = self.selenium.find_element_by_name("username")
username_input.send_keys('myuser')
password_input = self.selenium.find_element_by_name("password")
password_input.send_keys('secret')
self.selenium.find_element_by_xpath('//input[@value="Log in"]').click()
Finally, you may run the test as follows:
.. code-block:: bash
./manage.py test myapp.MySeleniumTests.test_login
This example will automatically open Firefox then go to the login page, enter
the credentials and press the "Log in" button. Selenium offers other drivers in
case you do not have Firefox installed or wish to use another browser. The
example above is just a tiny fraction of what the Selenium client can do; check
out the `full reference`_ for more details.
.. _Selenium: http://seleniumhq.org/
.. _selenium package: http://pypi.python.org/pypi/selenium
.. _full reference: http://selenium-python.readthedocs.org/en/latest/api.html
.. _Firefox: http://www.mozilla.com/firefox/
.. note::
``LiveServerTestCase`` makes use of the :doc:`staticfiles contrib app
</howto/static-files>` so you'll need to have your project configured
accordingly (in particular by setting :setting:`STATIC_URL`).
.. note::
When using an in-memory SQLite database to run the tests, the same database
connection will be shared by two threads in parallel: the thread in which
the live server is run and the thread in which the test case is run. It's
important to prevent simultaneous database queries via this shared
connection by the two threads, as that may sometimes randomly cause the
tests to fail. So you need to ensure that the two threads don't access the
database at the same time. In particular, this means that in some cases
(for example, just after clicking a link or submitting a form), you might
need to check that a response is received by Selenium and that the next
page is loaded before proceeding with further test execution.
Do this, for example, by making Selenium wait until the `<body>` HTML tag
is found in the response (requires Selenium > 2.13):
.. code-block:: python
def test_login(self):
from selenium.webdriver.support.wait import WebDriverWait
timeout = 2
...
self.selenium.find_element_by_xpath('//input[@value="Log in"]').click()
# Wait until the response is received
WebDriverWait(self.selenium, timeout).until(
lambda driver: driver.find_element_by_tag_name('body'))
The tricky thing here is that there's really no such thing as a "page load,"
especially in modern Web apps that generate HTML dynamically after the
server generates the initial document. So, simply checking for the presence
of `<body>` in the response might not necessarily be appropriate for all
use cases. Please refer to the `Selenium FAQ`_ and
`Selenium documentation`_ for more information.
.. _Selenium FAQ: http://code.google.com/p/selenium/wiki/FrequentlyAskedQuestions#Q:_WebDriver_fails_to_find_elements_/_Does_not_block_on_page_loa
.. _Selenium documentation: http://seleniumhq.org/docs/04_webdriver_advanced.html#explicit-waits
Test cases features
-------------------
Default test client
~~~~~~~~~~~~~~~~~~~
.. attribute:: TestCase.client
Every test case in a ``django.test.TestCase`` instance has access to an
instance of a Django test client. This client can be accessed as
``self.client``. This client is recreated for each test, so you don't have to
worry about state (such as cookies) carrying over from one test to another.
This means, instead of instantiating a ``Client`` in each test::
from django.utils import unittest
from django.test.client import Client
class SimpleTest(unittest.TestCase):
def test_details(self):
client = Client()
response = client.get('/customer/details/')
self.assertEqual(response.status_code, 200)
def test_index(self):
client = Client()
response = client.get('/customer/index/')
self.assertEqual(response.status_code, 200)
...you can just refer to ``self.client``, like so::
from django.test import TestCase
class SimpleTest(TestCase):
def test_details(self):
response = self.client.get('/customer/details/')
self.assertEqual(response.status_code, 200)
def test_index(self):
response = self.client.get('/customer/index/')
self.assertEqual(response.status_code, 200)
Customizing the test client
~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. attribute:: TestCase.client_class
If you want to use a different ``Client`` class (for example, a subclass
with customized behavior), use the :attr:`~TestCase.client_class` class
attribute::
from django.test import TestCase
from django.test.client import Client
class MyTestClient(Client):
# Specialized methods for your environment...
class MyTest(TestCase):
client_class = MyTestClient
def test_my_stuff(self):
# Here self.client is an instance of MyTestClient...
call_some_test_code()
.. _topics-testing-fixtures:
Fixture loading
~~~~~~~~~~~~~~~
.. attribute:: TestCase.fixtures
A test case for a database-backed Web site isn't much use if there isn't any
data in the database. To make it easy to put test data into the database,
Django's custom ``TestCase`` class provides a way of loading **fixtures**.
A fixture is a collection of data that Django knows how to import into a
database. For example, if your site has user accounts, you might set up a
fixture of fake user accounts in order to populate your database during tests.
The most straightforward way of creating a fixture is to use the
:djadmin:`manage.py dumpdata <dumpdata>` command. This assumes you
already have some data in your database. See the :djadmin:`dumpdata
documentation<dumpdata>` for more details.
.. note::
If you've ever run :djadmin:`manage.py syncdb<syncdb>`, you've
already used a fixture without even knowing it! When you call
:djadmin:`syncdb` in the database for the first time, Django
installs a fixture called ``initial_data``. This gives you a way
......@@ -1638,7 +1436,7 @@ Emptying the test outbox
If you use Django's custom ``TestCase`` class, the test runner will clear the
contents of the test email outbox at the start of each test case.
For more detail on email services during tests, see `Email services`_.
For more detail on email services during tests, see `Email services`_ below.
.. _assertions:
......@@ -1984,376 +1782,3 @@ under MySQL with MyISAM tables)::
@skipUnlessDBFeature('supports_transactions')
def test_transaction_behavior(self):
# ... conditional test code
Live test server
----------------
.. versionadded:: 1.4
.. currentmodule:: django.test
.. 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
(for example: ``myapp/tests.py``). The code for this test may look as follows:
.. code-block:: python
from django.test import LiveServerTestCase
from selenium.webdriver.firefox.webdriver import WebDriver
class MySeleniumTests(LiveServerTestCase):
fixtures = ['user-data.json']
@classmethod
def setUpClass(cls):
cls.selenium = WebDriver()
super(MySeleniumTests, cls).setUpClass()
@classmethod
def tearDownClass(cls):
cls.selenium.quit()
super(MySeleniumTests, cls).tearDownClass()
def test_login(self):
self.selenium.get('%s%s' % (self.live_server_url, '/login/'))
username_input = self.selenium.find_element_by_name("username")
username_input.send_keys('myuser')
password_input = self.selenium.find_element_by_name("password")
password_input.send_keys('secret')
self.selenium.find_element_by_xpath('//input[@value="Log in"]').click()
Finally, you may run the test as follows:
.. code-block:: bash
./manage.py test myapp.MySeleniumTests.test_login
This example will automatically open Firefox then go to the login page, enter
the credentials and press the "Log in" button. Selenium offers other drivers in
case you do not have Firefox installed or wish to use another browser. The
example above is just a tiny fraction of what the Selenium client can do; check
out the `full reference`_ for more details.
.. _Selenium: http://seleniumhq.org/
.. _selenium package: http://pypi.python.org/pypi/selenium
.. _full reference: http://selenium-python.readthedocs.org/en/latest/api.html
.. _Firefox: http://www.mozilla.com/firefox/
.. note::
``LiveServerTestCase`` makes use of the :doc:`staticfiles contrib app
</howto/static-files>` so you'll need to have your project configured
accordingly (in particular by setting :setting:`STATIC_URL`).
.. note::
When using an in-memory SQLite database to run the tests, the same database
connection will be shared by two threads in parallel: the thread in which
the live server is run and the thread in which the test case is run. It's
important to prevent simultaneous database queries via this shared
connection by the two threads, as that may sometimes randomly cause the
tests to fail. So you need to ensure that the two threads don't access the
database at the same time. In particular, this means that in some cases
(for example, just after clicking a link or submitting a form), you might
need to check that a response is received by Selenium and that the next
page is loaded before proceeding with further test execution.
Do this, for example, by making Selenium wait until the `<body>` HTML tag
is found in the response (requires Selenium > 2.13):
.. code-block:: python
def test_login(self):
from selenium.webdriver.support.wait import WebDriverWait
timeout = 2
...
self.selenium.find_element_by_xpath('//input[@value="Log in"]').click()
# Wait until the response is received
WebDriverWait(self.selenium, timeout).until(
lambda driver: driver.find_element_by_tag_name('body'))
The tricky thing here is that there's really no such thing as a "page load,"
especially in modern Web apps that generate HTML dynamically after the
server generates the initial document. So, simply checking for the presence
of `<body>` in the response might not necessarily be appropriate for all
use cases. Please refer to the `Selenium FAQ`_ and
`Selenium documentation`_ for more information.
.. _Selenium FAQ: http://code.google.com/p/selenium/wiki/FrequentlyAskedQuestions#Q:_WebDriver_fails_to_find_elements_/_Does_not_block_on_page_loa
.. _Selenium documentation: http://seleniumhq.org/docs/04_webdriver_advanced.html#explicit-waits
Using different testing frameworks
==================================
Clearly, :mod:`doctest` and :mod:`unittest` are not the only Python testing
frameworks. While Django doesn't provide explicit support for alternative
frameworks, it does provide a way to invoke tests constructed for an
alternative framework as if they were normal Django tests.
When you run ``./manage.py test``, Django looks at the :setting:`TEST_RUNNER`
setting to determine what to do. By default, :setting:`TEST_RUNNER` points to
``'django.test.simple.DjangoTestSuiteRunner'``. This class defines the default Django
testing behavior. This behavior involves:
#. Performing global pre-test setup.
#. Looking for unit tests and doctests in the ``models.py`` and
``tests.py`` files in each installed application.
#. Creating the test databases.
#. Running ``syncdb`` to install models and initial data into the test
databases.
#. Running the unit tests and doctests that are found.
#. Destroying the test databases.
#. Performing global post-test teardown.
If you define your own test runner class and point :setting:`TEST_RUNNER` at
that class, Django will execute your test runner whenever you run
``./manage.py test``. In this way, it is possible to use any test framework
that can be executed from Python code, or to modify the Django test execution
process to satisfy whatever testing requirements you may have.
.. _topics-testing-test_runner:
Defining a test runner
----------------------
.. currentmodule:: django.test.simple
A test runner is a class defining a ``run_tests()`` method. Django ships
with a ``DjangoTestSuiteRunner`` class that defines the default Django
testing behavior. This class defines the ``run_tests()`` entry point,
plus a selection of other methods that are used to by ``run_tests()`` to
set up, execute and tear down the test suite.
.. class:: DjangoTestSuiteRunner(verbosity=1, interactive=True, failfast=True, **kwargs)
``verbosity`` determines the amount of notification and debug information
that will be printed to the console; ``0`` is no output, ``1`` is normal
output, and ``2`` is verbose output.
If ``interactive`` is ``True``, the test suite has permission to ask the
user for instructions when the test suite is executed. An example of this
behavior would be asking for permission to delete an existing test
database. If ``interactive`` is ``False``, the test suite must be able to
run without any manual intervention.
If ``failfast`` is ``True``, the test suite will stop running after the
first test failure is detected.
Django will, from time to time, extend the capabilities of
the test runner by adding new arguments. The ``**kwargs`` declaration
allows for this expansion. If you subclass ``DjangoTestSuiteRunner`` or
write your own test runner, ensure accept and handle the ``**kwargs``
parameter.
.. versionadded:: 1.4
Your test runner may also define additional command-line options.
If you add an ``option_list`` attribute to a subclassed test runner,
those options will be added to the list of command-line options that
the :djadmin:`test` command can use.
Attributes
~~~~~~~~~~
.. attribute:: DjangoTestSuiteRunner.option_list
.. versionadded:: 1.4
This is the tuple of ``optparse`` options which will be fed into the
management command's ``OptionParser`` for parsing arguments. See the
documentation for Python's ``optparse`` module for more details.
Methods
~~~~~~~
.. method:: DjangoTestSuiteRunner.run_tests(test_labels, extra_tests=None, **kwargs)
Run the test suite.
``test_labels`` is a list of strings describing the tests to be run. A test
label can take one of three forms:
* ``app.TestCase.test_method`` -- Run a single test method in a test
case.
* ``app.TestCase`` -- Run all the test methods in a test case.
* ``app`` -- Search for and run all tests in the named application.
If ``test_labels`` has a value of ``None``, the test runner should run
search for tests in all the applications in :setting:`INSTALLED_APPS`.
``extra_tests`` is a list of extra ``TestCase`` instances to add to the
suite that is executed by the test runner. These extra tests are run
in addition to those discovered in the modules listed in ``test_labels``.
This method should return the number of tests that failed.
.. method:: DjangoTestSuiteRunner.setup_test_environment(**kwargs)
Sets up the test environment ready for testing.
.. method:: DjangoTestSuiteRunner.build_suite(test_labels, extra_tests=None, **kwargs)
Constructs a test suite that matches the test labels provided.
``test_labels`` is a list of strings describing the tests to be run. A test
label can take one of three forms:
* ``app.TestCase.test_method`` -- Run a single test method in a test
case.
* ``app.TestCase`` -- Run all the test methods in a test case.
* ``app`` -- Search for and run all tests in the named application.
If ``test_labels`` has a value of ``None``, the test runner should run
search for tests in all the applications in :setting:`INSTALLED_APPS`.
``extra_tests`` is a list of extra ``TestCase`` instances to add to the
suite that is executed by the test runner. These extra tests are run
in addition to those discovered in the modules listed in ``test_labels``.
Returns a ``TestSuite`` instance ready to be run.
.. method:: DjangoTestSuiteRunner.setup_databases(**kwargs)
Creates the test databases.
Returns a data structure that provides enough detail to undo the changes
that have been made. This data will be provided to the ``teardown_databases()``
function at the conclusion of testing.
.. method:: DjangoTestSuiteRunner.run_suite(suite, **kwargs)
Runs the test suite.
Returns the result produced by the running the test suite.
.. method:: DjangoTestSuiteRunner.teardown_databases(old_config, **kwargs)
Destroys the test databases, restoring pre-test conditions.
``old_config`` is a data structure defining the changes in the
database configuration that need to be reversed. It is the return
value of the ``setup_databases()`` method.
.. method:: DjangoTestSuiteRunner.teardown_test_environment(**kwargs)
Restores the pre-test environment.
.. method:: DjangoTestSuiteRunner.suite_result(suite, result, **kwargs)
Computes and returns a return code based on a test suite, and the result
from that test suite.
Testing utilities
-----------------
.. module:: django.test.utils
:synopsis: Helpers to write custom test runners.
To assist in the creation of your own test runner, Django provides a number of
utility methods in the ``django.test.utils`` module.
.. function:: setup_test_environment()
Performs any global pre-test setup, such as the installing the
instrumentation of the template rendering system and setting up
the dummy email outbox.
.. function:: teardown_test_environment()
Performs any global post-test teardown, such as removing the black
magic hooks into the template system and restoring normal email
services.
.. currentmodule:: django.db.connection.creation
The creation module of the database backend (``connection.creation``)
also provides some utilities that can be useful during testing.
.. function:: create_test_db([verbosity=1, autoclobber=False])
Creates a new test database and runs ``syncdb`` against it.
``verbosity`` has the same behavior as in ``run_tests()``.
``autoclobber`` describes the behavior that will occur if a
database with the same name as the test database is discovered:
* If ``autoclobber`` is ``False``, the user will be asked to
approve destroying the existing database. ``sys.exit`` is
called if the user does not approve.
* If autoclobber is ``True``, the database will be destroyed
without consulting the user.
Returns the name of the test database that it created.
``create_test_db()`` has the side effect of modifying the value of
:setting:`NAME` in :setting:`DATABASES` to match the name of the test
database.
.. function:: destroy_test_db(old_database_name, [verbosity=1])
Destroys the database whose name is the value of :setting:`NAME` in
:setting:`DATABASES`, and sets :setting:`NAME` to the value of
``old_database_name``.
The ``verbosity`` argument has the same behavior as for
:class:`~django.test.simple.DjangoTestSuiteRunner`.
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