feature/BE-39: Backend Unittests [1]

[KarahanS]

As stated in #370, purpose of this PR is to add new unit tests to cover functionalities provided by our APIs. PR includes following additions:

• Added xmlrunner.extra.djangotestrunner.XMLTestRunner to base.py to generate test output in xml format. Whenever the unittests are run, xml files will be generated and collected in test-output folder. If you are running the tests within the App/backend directory, you can simply call rm test-output/* to clear the content of the folder.
• Implemented ~45 new unit tests. User RequestFactory to send API requests. You can run all the unittest at once with the following command:

  python manage.py test .

  Additionally, you can run a specific function using the command below:

  python manage.py test -k <name_of_the_function>

  Added these commands to README.
• Made minor corrections on the documentation as I spot some errors while working on the unittests.
• Added utils.py to test folder to store some of the common operations - which can be useful for all unittests.

[BElifb]

• Ran the tests, they were all successful.
• Also tried running a single test with the given command, worked as well.
• One thing to add could be, all of the tests about a specific functionality (e.g. artitem) appeared with the same name in the terminal. I was able to see specific names in the xml files, so this is not absolutely necessary.
• Thank you for utils.py. Also if you share any of the resources you used while preparing the tests, it would be much appreciated.

[KarahanS]

Thanks for the review.

• Thank you for utils.py. Also if you share any of the resources you used while preparing the tests, it would be much appreciated.

• While I was preparing the tests, I used some documentation and lots of Stackoverflow. Some of the ones I found helpful:
  • https://docs.djangoproject.com/en/4.1/topics/testing/advanced/
  • http://www.tomchristie.com/rest-framework-2-docs/api-guide/testing
• Most probably, all these unittests I've implemented, cover everything new that we have to use to implement unittests. Therefore you can refer to them anytime you want while implementing yours. They may seem complicated at first sight, but nope - very straightforward when you get used to them.