Django test FileField using test fixtures

Question

I\'m trying to build tests for some models that have a FileField. The model looks like this:

class SolutionFile(models.Model):
    \'\'\'
    A file from a s         


        

Answer 1

Django provides a great way to write tests on FileFields without mucking about in the real filesystem - use a SimpleUploadedFile.

from django.core.files.uploadedfile import SimpleUploadedFile

my_model.file_field = SimpleUploadedFile('best_file_eva.txt', b'these are the contents of the txt file')

It's one of django's magical features-that-don't-show-up-in-the-docs :). However it is referred to here.

Answer 2

This is what I did for my test. After uploading the file it should end up in the photo property of my organization model object:

    import tempfile
    filename = tempfile.mkstemp()[1]
    f = open(filename, 'w')
    f.write('These are the file contents')
    f.close()
    f = open(filename, 'r')
    post_data = {'file': f}
    response = self.client.post("/org/%d/photo" % new_org_data["id"], post_data)
    f.close()
    self.assertEqual(response.status_code, 200)

    ## Check the file
    ## org is where the file should end up
    org = models.Organization.objects.get(pk=new_org_data["id"])
    self.assertEqual("These are the file contents", org.photo.file.read())

    ## Remove the file
    import os
    os.remove(org.photo.path)

Answer 3

You can override the MEDIA_ROOT setting for your tests using the @override_settings() decorator as documented:

from django.test import override_settings


@override_settings(MEDIA_ROOT='/tmp/django_test')
def test_post_solution_file(self):
  # your code here

Answer 4

with pytest and pytest-django, I use this in conftest.py file:

import tempfile
import shutil
from pytest_django.lazy_django import skip_if_no_django
from pytest_django.fixtures import SettingsWrapper


@pytest.fixture(scope='session')
#@pytest.yield_fixture()
def settings():
    """A Django settings object which restores changes after the testrun"""
    skip_if_no_django()

    wrapper = SettingsWrapper()
    yield wrapper
    wrapper.finalize()


@pytest.fixture(autouse=True, scope='session')
def media_root(settings):
    tmp_dir = tempfile.mkdtemp()
    settings.MEDIA_ROOT = tmp_dir
    yield settings.MEDIA_ROOT
    shutil.rmtree(tmp_dir)


@pytest.fixture(scope='session')
def django_db_setup(media_root, django_db_setup):
    print('inject_after')

might be helpful:

1. https://dev.funkwhale.audio/funkwhale/funkwhale/blob/de777764da0c0e9fe66d0bb76317679be964588b/api/tests/conftest.py
2. https://framagit.org/ideascube/ideascube/blob/master/conftest.py
3. https://stackoverflow.com/a/56177770/5305401

Answer 5

I've written unit tests for an entire gallery app before, and what worked well for me was using the python tempfile and shutil modules to create copies of the test files in temporary directories and then delete them all afterwards.

The following example is not working/complete, but should get you on the right path:

import os, shutil, tempfile

PATH_TEMP = tempfile.mkdtemp(dir=os.path.join(MY_PATH, 'temp'))

def make_objects():
    filenames = os.listdir(TEST_FILES_DIR)

    if not os.access(PATH_TEMP, os.F_OK):
        os.makedirs(PATH_TEMP)

    for filename in filenames:
        name, extension = os.path.splitext(filename)
        new = os.path.join(PATH_TEMP, filename)
        shutil.copyfile(os.path.join(TEST_FILES_DIR, filename), new)

        #Do something with the files/FileField here

def remove_objects():
    shutil.rmtree(PATH_TEMP)

I run those methods in the setUp() and tearDown() methods of my unit tests and it works great! You've got a clean copy of your files to test your filefield that are reusable and predictable.