Django: How to create a model dynamically just for testing

Question

I have a Django app that requires a settings attribute in the form of:

RELATED_MODELS = (\'appname1.modelname1.attribute1\',
                  \         


        

Answer 1

Here's the pattern that I'm using to do this.

I've written this method that I use on a subclassed version of TestCase. It goes as follows:

@classmethod
def create_models_from_app(cls, app_name):
    """
    Manually create Models (used only for testing) from the specified string app name.
    Models are loaded from the module ".models"
    """
    from django.db import connection, DatabaseError
    from django.db.models.loading import load_app

    app = load_app(app_name)
    from django.core.management import sql
    from django.core.management.color import no_style
    sql = sql.sql_create(app, no_style(), connection)
    cursor = connection.cursor()
    for statement in sql:
        try:
            cursor.execute(statement)
        except DatabaseError, excn:
            logger.debug(excn.message)
            pass

Then, I create a special test-specific models.py file in something like myapp/tests/models.py that's not included in INSTALLED_APPS.

In my setUp method, I call create_models_from_app('myapp.tests') and it creates the proper tables.

The only "gotcha" with this approach is that you don't really want to create the models ever time setUp runs, which is why I catch DatabaseError. I guess the call to this method could go at the top of the test file and that would work a little better.