Contributing a patch

Note

For more background on the material covered in this how-to section, see the Contributing code and Running and writing tests sections of the documentation.

django CMS is an open project, and welcomes the participation of anyone who would like to contribute, whatever their any level of knowledge.

As well as code, we welcome contributions to django CMS’s documentation and translations.

Note

Feel free to dive into coding for django CMS in whichever way suits you. However, you need to be aware of the guidelines and policies for django CMS project development. Adhering to them will make much easier for the core developers to validate and accept your contribution.

The basics

The basic workflow for a code contribution will typically run as follows:

  1. Fork the django CMS project GitHub repository to your own GitHub account

  2. Clone your fork locally:

    1. git clone git@github.com:YOUR_USERNAME/django-cms.git

  3. Create a virtualenv:

    1. virtualenv cms-develop
    2. source cms-develop/bin/activate

  4. Install its dependencies:

    1. cd django-cms
    2. pip install -r test_requirements/django-X.Y.txt

    Replace X.Y with whichever version of Django you want to work with.

  5. Create a new branch for your work:

    1. git checkout -b my_fix

  6. Edit the django CMS codebase to implement the fix or feature.

  7. Run the test suite:

    1. python manage.py test

  8. Commit and push your code:

    1. git commit
    2. git push origin my_fix

  9. Open a pull request on GitHub.

Target branches

See Branches for information about branch policy.

How to write a test

The django CMS test suite contains a mix of unit tests, functional tests, regression tests and integration tests.

Depending on your contribution, you will write a mix of them.

Let’s start with something simple. We’ll assume you have set up your environment correctly as described above.

Let’s say you want to test the behaviour of the CMSPluginBase.render method:

  1. class CMSPluginBase(six.with_metaclass(CMSPluginBaseMetaclass, admin.ModelAdmin)):
  3.     ...
  5.     def render(self, context, instance, placeholder):
  6.         context['instance'] = instance
  7.         context['placeholder'] = placeholder
  8.         return context

Writing a unit test for it will require us to test whether the returned context object contains the declared attributes with the correct values.

We will start with a new class in an existing django CMS test module (cms.tests.plugins in this case):

  1. class SimplePluginTestCase(CMSTestCase):
  2.     pass

Let’s try to run it:

  1. python manage.py test cms.tests.test_plugins.SimplePluginTestCase

This will call the new test case class only and it’s handy when creating new tests and iterating quickly through the steps. A full test run (python manage.py test) is required before opening a pull request.

This is the output you’ll get:

  1. Creating test database for alias 'default'...
  3. ----------------------------------------------------------------------
  4. Ran 0 tests in 0.000s
  6. OK

Which is correct as we have no test in our test case. Let’s add an empty one:

  1. class SimplePluginTestCase(CMSTestCase):
  3.     def test_render_method(self):
  4.         pass

Running the test command again will return a slightly different output:

  1. Creating test database for alias 'default'...
  2. .
  3. ----------------------------------------------------------------------
  4. Ran 1 test in 0.001s
  6. OK

This looks better, but it’s not that meaningful as we’re not testing anything.

Write a real test:

  1. class SimplePluginTestCase(CMSTestCase):
  3.     def test_render_method(self):
  4.         """
  5.         Tests the CMSPluginBase.render method by checking that the appropriate variables
  6.         are set in the returned context
  7.         """
  8.         from cms.api import create_page
  9.         my_page = create_page('home', language='en', template='col_two.html')
  10.         placeholder = my_page.placeholders.get(slot='col_left')
  11.         context = self.get_context('/', page=my_page)
  12.         plugin = CMSPluginBase()
  14.         new_context = plugin.render(context, None, placeholder)
  15.         self.assertTrue('placeholder' in new_context)
  16.         self.assertEqual(placeholder, context['placeholder'])
  17.         self.assertTrue('instance' in new_context)
  18.         self.assertIsNone(new_context['instance'])

and run it:

  1. Creating test database for alias 'default'...
  2. .
  3. ----------------------------------------------------------------------
  4. Ran 1 test in 0.044s
  6. OK

The output is quite similar to the previous run, but the longer execution time gives us a hint that this test is actually doing something.

Let’s quickly check the test code.

To test CMSPluginBase.render method we need a RequestContext instance and a placeholder. As CMSPluginBase does not have any configuration model, the instance argument can be None.

  1. Create a page instance to get the placeholder
  2. Get the placeholder by filtering the placeholders of the page instance on the expected placeholder name
  3. Create a context instance by using the provided super class method
  4. Call the render method on a CMSPluginBase instance; being stateless, it’s easy to call render of a bare instance of the CMSPluginBase class, which helps in tests
  5. Assert a few things the method must provide on the returned context instance

As you see, even a simple test like this assumes and uses many feature of the test utilities provided by django CMS. Before attempting to write a test, take your time to explore the content of cms.test_utils package and check the shipped templates, example applications and, most of all, the base testcases defined in cms.test_utils.testscases which provide a lot of useful methods to prepare the environment for our tests or to create useful test data.

Submitting your code

After the code and the tests are ready and packed in commits, you must submit it for review and merge in the django CMS GitHub project.

As noted above, always create a new branch for your code, be it a fix or a new feature, before committing changes, then create your pull request from your branch to the target branch on django CMS.

Acceptance criteria

Matching these criteria from the very beginning will help the core developers to be able to review your submission more quickly and efficiently and will increase the chances of making a successful pull request.

Please see our Development policies for guidance on which branches to use, how to prepare pull requests and so on.

Features

To be accepted, proposed features should have at least:

  • natural language documentation in the docs folder describing the feature, its usage and potentially backward incompatibilities.
  • inline documentation (comments and docstrings) in the critical areas of the code explaining the behaviour
  • appropriate test coverage
  • Python 2/3 compatibility
  • Django migrations (where applicable)

The pull request description must briefly describe the feature and the intended goal and benefits.

Bugs

To be accepted, proposed bug fixes should have at least:

  • inline documentation (comments and docstrings) in the critical areas of the code explaining the behaviour
  • at least 1 regression test that demonstrates the issue and the fix
  • Python 2/3 compatibility
  • Django migrations (where applicable)

The pull request description must briefly describe the bug and the steps for its solution; in case the bug has been opened elsewhere, it must be linked in the pull request description, describing the fix.