How to test file upload in pytest?

Question

How to serializer a file object while using json.dumps ?

I 'm using pytest for testing file upload in django and I 've this function

def test_file_upload(self):
     # file_content is a bytest object
     request = client.patch(
        "/fake-url/",
        json.dumps({"file" : file_content}),
        content_type="application/json",
    )

I 've tried to set the file_content as a bytes object but I 'm getting this error TypeError: Object of type bytes is not JSON serializable I need to send the whole file to my endpoint as json serialized

File bytes cannot be serialized to JSON. What is your backend expecting ? A multipart form/data or the file encoded as a base64 string ? — May.D, Dec 07 '22 at 12:23
So just base64 encode `file_content` and you should be fine. — May.D, Dec 07 '22 at 12:35
I tried this but still have same error I tried to use `file = base64.b64encode(file_content)` and send file instead — Mohamed Ibrahim, Dec 07 '22 at 13:30

score 2 · Answer 1 · answered Dec 07 '22 at 12:26

You can use it mock library for testing file upload;

from mock import MagicMock
from django.core.files import File

mock_image = magicMock(file=File)
mock_image.name="sample.png"

# Another test operations...

def test_file_upload(self):
     # file_content is a bytest object
     request = client.patch(
        "/fake-url/",
        {"file" : mock_image},
        format="multipart",
    )

Detailed another answer; how to unit test file upload in django

May.D · Answer 2 · 2022-12-07T14:49:54.630

1

Your API endpoint expects a multipart form containing file. Below is the function I use to send a multipart form from a local file for testing. If you already have file bytes, skip the open line and just use file_content in ContentFile.

def send_multipart_form(self, filename):
    with open(filename, "rb") as f:
        file_data = ContentFile(f.read(), os.path.basename(filename))
        res = self.client.put(
            self.url,
            data=encode_multipart(boundary=BOUNDARY, data={"file": file_data}),
            content_type=MULTIPART_CONTENT,
        )
        return res

edited Dec 07 '22 at 14:49

answered Dec 07 '22 at 13:42

May.D

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I tried this but for same reason it returns `400` error but works well while trying to update another field other than the file – Mohamed Ibrahim Dec 07 '22 at 13:51
What error message do you get with the 400 error ? – May.D Dec 07 '22 at 13:59
It doesn't show up the whole error but all I 'm using is just django rest framework view and serializer for my model @May.D – Mohamed Ibrahim Dec 07 '22 at 14:28
If file is a FileField in your model, it does not expect a base64 string. You need to send a multipart form with your file. – May.D Dec 07 '22 at 14:31
Yes it's a filefield in django model , how to send a multipart ? – Mohamed Ibrahim Dec 07 '22 at 14:34

How to test file upload in pytest?

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