Factory Boy

FileField

class Record(TimeStampedModel):

    original_file = models.FileField(
        blank=True,
        upload_to='record/original',
        storage=private_file_store,
    )

import factory

class RecordFactory(factory.django.DjangoModelFactory):

    class Meta:
        model = Record

    original_file = factory.django.FileField()

# put some data into the file
RecordFactory(original_file__data=b'abc')

Note

For the __data=b' feature to work, we need to set the field to a factory.django.FileField() in the factory.

Many to Many

Here is the model:

products = models.ManyToManyField(Product, related_name='+')

And the factory:

enrol = StockFactory(products=[product])

@factory.post_generation
def products(self, create, extracted, **kwargs):
    if not create:
        # Simple build, do nothing.
        return
    if extracted:
        # A list of products were passed in, use them
        for product in extracted:
            self.products.add(product)

Issues

If you get a no such table error:

django.db.utils.OperationalError: no such table: member_contact

I have found two reasons why this might be:

It is because you are not using the SubFactory correctly.

These lines will throw an error because the factory is being instantiated before the test has started running:
contact = ContactFactory()
contact = factory.SubFactory(ContactFactory())
This is the correct version:
contact = factory.SubFactory(ContactFactory)
For more information, see the answer to this question: Factory fails when invoked in definition of another factory

Your model name starts with the word Test e.g. TestTask.

This will cause an error because your factory will be in the tests folder and will be called TestTaskFactory. The test runner (in my case py.test will see the factory and think it is a test. The database isn’t set-up at this stage so you will get the no such table error!