mirror of https://github.com/django/django.git
112 lines
4.2 KiB
Plaintext
112 lines
4.2 KiB
Plaintext
=================
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Testing in Django
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=================
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.. toctree::
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:hidden:
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overview
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doctests
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advanced
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Automated testing is an extremely useful bug-killing tool for the modern
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Web developer. You can use a collection of tests -- a **test suite** -- to
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solve, or avoid, a number of problems:
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* When you're writing new code, you can use tests to validate your code
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works as expected.
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* When you're refactoring or modifying old code, you can use tests to
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ensure your changes haven't affected your application's behavior
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unexpectedly.
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Testing a Web application is a complex task, because a Web application is made
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of several layers of logic -- from HTTP-level request handling, to form
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validation and processing, to template rendering. With Django's test-execution
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framework and assorted utilities, you can simulate requests, insert test data,
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inspect your application's output and generally verify your code is doing what
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it should be doing.
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The best part is, it's really easy.
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Unit tests v. doctests
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======================
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There are two primary ways to write tests with Django, corresponding to the
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two test frameworks that ship in the Python standard library. The two
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frameworks are:
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* **Unit tests** -- tests that are expressed as methods on a Python class
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that subclasses :class:`unittest.TestCase` or Django's customized
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:class:`TestCase`. For example::
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import unittest
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class MyFuncTestCase(unittest.TestCase):
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def testBasic(self):
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a = ['larry', 'curly', 'moe']
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self.assertEqual(my_func(a, 0), 'larry')
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self.assertEqual(my_func(a, 1), 'curly')
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* **Doctests** -- tests that are embedded in your functions' docstrings and
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are written in a way that emulates a session of the Python interactive
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interpreter. For example::
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def my_func(a_list, idx):
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"""
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>>> a = ['larry', 'curly', 'moe']
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>>> my_func(a, 0)
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'larry'
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>>> my_func(a, 1)
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'curly'
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"""
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return a_list[idx]
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Which should I use?
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-------------------
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Because Django supports both of the standard Python test frameworks, it's up to
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you and your tastes to decide which one to use. You can even decide to use
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*both*.
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For developers new to testing, however, this choice can seem confusing. Here,
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then, are a few key differences to help you decide which approach is right for
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you:
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* If you've been using Python for a while, :mod:`doctest` will probably feel
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more "pythonic". It's designed to make writing tests as easy as possible,
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so it requires no overhead of writing classes or methods. You simply put
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tests in docstrings. This has the added advantage of serving as
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documentation (and correct documentation, at that!). However, while
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doctests are good for some simple example code, they are not very good if
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you want to produce either high quality, comprehensive tests or high
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quality documentation. Test failures are often difficult to debug
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as it can be unclear exactly why the test failed. Thus, doctests should
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generally be avoided and used primarily for documentation examples only.
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* The :mod:`unittest` framework will probably feel very familiar to
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developers coming from Java. :mod:`unittest` is inspired by Java's JUnit,
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so you'll feel at home with this method if you've used JUnit or any test
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framework inspired by JUnit.
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* If you need to write a bunch of tests that share similar code, then
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you'll appreciate the :mod:`unittest` framework's organization around
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classes and methods. This makes it easy to abstract common tasks into
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common methods. The framework also supports explicit setup and/or cleanup
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routines, which give you a high level of control over the environment
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in which your test cases are run.
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* If you're writing tests for Django itself, you should use :mod:`unittest`.
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Where to go from here
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=====================
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As unit tests are preferred in Django, we treat them in detail in the
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:doc:`overview` document.
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:doc:`doctests` describes Django-specific features when using doctests.
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You can also use any *other* Python test framework, Django provides an API and
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tools for that kind of integration. They are described in the
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:ref:`other-testing-frameworks` section of :doc:`advanced`.
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