How can I test binary file uploading with django-rest-framework's test client?

Question

I have a Django application with a view that accepts a file to be uploaded. Using the Django REST framework I\'m subclassing APIView and implementing the post() method like

Answer 1

When testing file uploads, you should pass the stream object into the request, not the data.

This was pointed out in the comments by @arocks

Pass { 'image': file} instead

But that didn't full explain why it was needed (and also didn't match the question). For this specific question, you should be doing

from PIL import Image

class TestFileUpload(APITestCase):

    def test_file_is_accepted(self):
        self.client.force_authenticate(self.user)

        image = Image.new('RGB', (100, 100))

        tmp_file = tempfile.NamedTemporaryFile(suffix='.jpg')
        image.save(tmp_file)
        tmp_file.seek(0)

        response = self.client.post('my_url', {'image': tmp_file}, format='multipart')

       self.assertEqual(status.HTTP_201_CREATED, response.status_code)

This will match a standard Django request, where the file is passed in as a stream object, and Django REST Framework handles it. When you just pass in the file data, Django and Django REST Framework interpret it as a string, which causes issues because it is expecting a stream.

And for those coming here looking to another common error, why file uploads just won't work but normal form data will: make sure to set format="multipart" when creating the request.

This also gives a similar issue, and was pointed out by @RobinElvin in the comments

It was because I was missing format='multipart'