How to test django.forms.ImageField

forms.py

from django import forms


class PhotoForm(forms.Form):
    image = forms.ImageField()

tests.py

from django.test import TestCase


class PhotoFormTest(TestCase):
    def test_valid(self):
        from django.core.files.uploadedfile import InMemoryUploadedFile
        from StringIO import StringIO
        image = InMemoryUploadedFile(
            StringIO(TEST_IMAGE),
            field_name='tempfile',
            name='tempfile.png',
            content_type='image/png',
            size=len(TEST_IMAGE),
            charset='utf-8',
        )
        from forms import PhotoForm
        form = PhotoForm(files={'image': image})

        self.assertEqual(form.is_valid(), True)

TEST_IMAGE = '''
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'''.strip().decode('base64')

Nice, thanks, helped me a lot.
For python 3 it requires some changes, I have added comments in changed lines:

import base64               # for decoding base64 image
import tempfile             # for setting up tempdir for media
from django.test import TestCase, override_settings


class PhotoFormTest(TestCase):
    @override_settings(MEDIA_ROOT=tempfile.gettempdir())      # override settings for media dir to avoid filling up your disk
    def test_valid(self):
        from django.core.files.uploadedfile import InMemoryUploadedFile
        from io import BytesIO                                # StringIO and BytesIO are parts of io module in python3
        image = InMemoryUploadedFile(
            BytesIO(base64.b64decode(TEST_IMAGE)),            # use io.BytesIO
            field_name='tempfile',
            name='tempfile.png',
            content_type='image/png',
            size=len(TEST_IMAGE),
            charset='utf-8',
        )
        from forms import PhotoForm
        form = PhotoForm(files={'image': image})

        self.assertEqual(form.is_valid(), True)

TEST_IMAGE = '''
iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBI
WXMAAABIAAAASABGyWs+AAAACXZwQWcAAAAQAAAAEABcxq3DAAABfElEQVQ4y52TvUuCURTGf5Zg
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'''.strip()                                              # no need of decode here anymore