Now that you have had a walkthrough of the sample application, let's take a look at how you can run tests locally to verify that the application is functioning as expected. The todobackend application includes a small set of tests for Todo items that are located in the src/todo/tests.py file. Understanding how these tests are written is outside the scope of this book, however knowing how to run these tests is critical in being able to test, build, and ultimately package the application into a Docker image.
When testing your application, it is very common to have additional dependencies that are specific to application testing, and are not required if you are building your application to run in production. This sample application defines test dependencies in a file called src/requirements_test.txt, which imports all of the core application dependencies in src/requirements.txt and adds additional test-specific dependencies:
-r requirements.txt
colorama==0.3.9
coverage==4.4.2
django-nose==1.4.5
nose==1.3.7
pinocchio==0.4.2
To install these requirements, you need to the run the PIP package manager, referencing the requirements_test.txt file:
src> pip3 install -r requirements_test.txt --user
Requirement already satisfied: Django==2.0 in /usr/local/lib/python3.7/site-packages (from -r requirements.txt (line 1)) (2.0)
Requirement already satisfied: django-cors-headers==2.1.0 in /usr/local/lib/python3.7/site-packages (from -r requirements.txt (line 2)) (2.1.0)
...
...
Installing collected packages: django-coverage, nose, django-nose, pinocchio
Successfully installed django-nose-1.4.5 pinocchio-0.4.2
You can now run tests for the sample application by running the python3 manage.py test command, passing in the --settings flag, which allows you specify a custom settings configuration. In the sample application, there are additional test settings which are defined in the src/todobackend/settings_test.py file that extend the default settings included in src/todobackend/settings.py, which add testing enhancements such as specs style formatting and code coverage statistics:
src> python3 manage.py test --settings todobackend.settings_test
Creating test database for alias 'default'...
Ensure we can create a new todo item
- item has correct title
- item was created
- received 201 created status code
- received location header hyperlink
Ensure we can delete all todo items
- all items were deleted
- received 204 no content status code
Ensure we can delete a todo item
- received 204 no content status code
- the item was deleted
Ensure we can update an existing todo item using PATCH
- item was updated
- received 200 ok status code
Ensure we can update an existing todo item using PUT
- item was updated
- received 200 created status code
----------------------------------------------------------------------
XML: /Users/jmenga/todobackend/src/unittests.xml
Name Stmts Miss Cover
-----------------------------------------------------
todo/__init__.py 0 0 100%
todo/admin.py 1 1 0%
todo/migrations/0001_initial.py 5 0 100%
todo/migrations/__init__.py 0 0 100%
todo/models.py 6 6 0%
todo/serializers.py 7 0 100%
todo/urls.py 6 0 100%
todo/views.py 17 0 100%
-----------------------------------------------------
TOTAL 42 7 83%
----------------------------------------------------------------------
Ran 12 tests in 0.281s
OK
Destroying test database for alias 'default'...
Notice that Django test runner scans the various folders in the repository for tests, creates a test database, and then runs each test. After all tests are complete, the test runner automatically destroys the test database, so you don't have to perform any manual setup or cleanup tasks.