More than just preventing "bad" or "incomplete" data, an application's models can enforce domain rules & requirements. Most applications take a layered approach to data integrity.
| Database | Model | Interface |
|---|---|---|
| Core | Middle Layer | Outer Layer |
At the outermost layer, you have the program's interface, e.g. an HTML form that only allows a user to enter an email address that contains @.
The next level of validation is often performed by the application's models. One approach might be to overwrite the .save method like so:
def save(self, *args, **kwargs):
if len(self.first_name) < 1
raise ValidationError(_('Name must be longer than one letter'), code='invalid')
super(SwimRecord, self).save(*args, **kwargs)
While this works, it isn't very scalable. Django takes a different approach.
The final level of validation is usually performed by the database. Often with NOT NULL constraints or particular column types (integer vs varchar(255) or char(14)).
This challenge will have you exploring the Django docs (and any other resources you find online) to resolve some errors and ultimately make the tests pass. We are working with one model. The attributes are written for you and commented out - they are also incomplete. You'll have to add some settings to what is there to get the first few tests to pass.
The last batch of tests will require you to write your own validations.
Create a virtual env. Start it up. Then tell pip to read the requirements.txt file and install all the requirements.
python -m venv venv
source venv/bin/activate
pip install -r requirements.txt
Run the test with the following command.
python manage.py testThe first four tests will pass because of the nature of full_clean(). We've commented out the attributes in the model. Your job is to figure out what code needs to be added to each attribute to truly pass each test.
If you get an error saying the test db already exists you should be able to type yes to destroy it and create a new one.
Using the skeleton found in models.py, your job is to uncomment out each column one by one and make the tests pass.
This challenge includes one model SwimRecord. Follow the tests in swimrecords/tests.py, adding any missing validations using those provided by Django
Some validations can be implemented by using functions provided by Django, but for some tests, you'll need to create your own validation methods.