Error creating object with ImageField

[fcasco]

Given a factory with this code:

class SomeFactory(factory.DjangoModelFactory):

class Meta:
    model = SomeModel

image_field = factory.django.ImageField(filename='registration.jpg', width=1, height=1)

When I try to create the object using SomeFactory.create() I get this traceback:

Traceback (most recent call last:
  File "tests_frontend.py", line 351, in test_card_activation
    registration = SomeFactory.create()
  File "env/lib/python2.7/site-packages/factory/base.py", line 559, in create
    return cls._generate(True, attrs)
  File "env/lib/python2.7/site-packages/factory/base.py", line 484, in _generate
    obj = cls._prepare(create, **attrs)
  File "env/lib/python2.7/site-packages/factory/base.py", line 459, in _prepare
    return cls._create(model_class, *args, **kwargs)
  File "env/lib/python2.7/site-packages/factory/django.py", line 149, in _create
    return manager.create(*args, **kwargs)
  File "env/lib/python2.7/site-packages/django/db/models/manager.py", line 137, in create
    return self.get_query_set().create(**kwargs)
  File "env/lib/python2.7/site-packages/django/db/models/query.py", line 377, in create
    obj.save(force_insert=True, using=self.db)
  File "env/lib/python2.7/site-packages/django/db/models/base.py", line 463, in save
    self.save_base(using=using, force_insert=force_insert, force_update=force_update)
  File "env/lib/python2.7/site-packages/django/db/models/base.py", line 551, in save_base
    result = manager._insert([self], fields=fields, return_id=update_pk, using=using, raw=raw)
  File "env/lib/python2.7/site-packages/django/db/models/manager.py", line 203, in _insert
    return insert_query(self.model, objs, fields, **kwargs)
  File "env/lib/python2.7/site-packages/django/db/models/query.py", line 1593, in insert_query
    return query.get_compiler(using=using).execute_sql(return_id)
  File "env/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 911, in execute_sql
    for sql, params in self.as_sql():
  File "env/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 872, in as_sql
    for obj in self.query.objs
  File "env/lib/python2.7/site-packages/django/db/models/fields/files.py", line 249, in pre_save
    file.save(file.name, file, save=False)
  File "env/lib/python2.7/site-packages/django/db/models/fields/files.py", line 90, in save
    self._size = content.size
  File "env/lib/python2.7/site-packages/django/db/models/fields/files.py", line 70, in _get_size
    return self.file.size
  File "env/lib/python2.7/site-packages/django/core/files/base.py", line 39, in _get_size
    elif os.path.exists(self.file.name):
AttributeError: 'cStringIO.StringI' object has no attribute 'name'

I was expecting the instance would be created with an image

[rbarrois]

Indeed, this is a known issue with factory.django.FileField and factory.django.ImageField that are implemented as post-build fields, thus not available in the field's save() method.

[fcasco]

I solved using this code:

    image = factory.LazyAttribute(lambda o: ContentFile(
                                  factory.django.ImageField()._make_data(
                                    {'width': 8, 'height': 8, 'format': 'png'}), 'benefit.png'))