Flask test_client can't handle HTTP 204 No data

Question

I have delete endpoint, returning HTTP 204

@blueprint.route('/foo', methods=['DELETE'])
def delete_tag(id):
    # ....
    return '', 204

and I want to test it

def test_delete_tag(self):
    resp = self.client.delete(url_for('tags.delete_tag', id=1))
    self.assertEqual(resp.status_code, 204)

but I got exception

Traceback (most recent call last):
  File "tests/tags_test.py", line 31, in test_delete_tag
    resp = self.client.delete(url_for('tags.delete_tag', id=1)})
  File ".virtualenvs/...site-packages/werkzeug/test.py", line 799, in delete
    return self.open(*args, **kw)
  File ".virtualenvs/...site-packages/flask/testing.py", line 108, in open
    follow_redirects=follow_redirects)
  File ".virtualenvs/...site-packages/werkzeug/test.py", line 742, in open
    response = self.run_wsgi_app(environ, buffered=buffered)
  File ".virtualenvs/...site-packages/werkzeug/test.py", line 659, in run_wsgi_app
    rv = run_wsgi_app(self.application, environ, buffered=buffered)
  File ".virtualenvs/.../site-packages/werkzeug/test.py", line 885, in run_wsgi_app
    buffer.append(next(app_iter))
StopIteration

with response status 200 it works all fine. Is there way how to fix the test?

Answer 1

The mining of 204 is "no content" at all, it's assume that you're not going to add any body in that response.