Django testing model with ImageField

For future users, I've solved the problem. You can mock an ImageField with a SimpleUploadedFile instance.

test.py

from django.core.files.uploadedfile import SimpleUploadedFile

newPhoto.image = SimpleUploadedFile(name='test_image.jpg', content=open(image_path, 'rb').read(), content_type='image/jpeg')

You can use a temporary file, using tempfile. So you don't need a real file to do your tests.

import tempfile

image = tempfile.NamedTemporaryFile(suffix=".jpg").name

If you prefer to do manual clean-up, use tempfile.mkstemp() instead.

Tell the mock library to create a mock object based on Django's File class

import mock
from django.core.files import File

file_mock = mock.MagicMock(spec=File, name='FileMock')

and then use in your tests

newPhoto.image = file_mock

If you don't want to create an actual file in the filesystem, you can use this 37-byte GIF instead, small enough to a be a bytes literal in your code:

from django.core.files.uploadedfile import SimpleUploadedFile

small_gif = (
    b'\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x00\x00\x00\x21\xf9\x04'
    b'\x01\x0a\x00\x01\x00\x2c\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02'
    b'\x02\x4c\x01\x00\x3b'
)
uploaded = SimpleUploadedFile('small.gif', small_gif, content_type='image/gif')