generators.py

from PIL import Image


def random_image(size=(200, 200)):
    """ Generates a random PIL image, for testings propouse.

    :param size: Size of the random image generated.
    """
    color = (random.randint(0, 255), random.randint(0, 255), random.randint(0, 255), 0)
    return Image.new("RGBA", size, color)

test.py

import StringIO


def test_picture_form(self):
    """Sample of test."""
    picture = random_image()
    picture_file = StringIO.StringIO()
    picture.save(picture_file, format="JPEG")
    
    # Use picture for testing...