Flask test_client: Testing DELETE request with data

Question

I'm trying to test my Flask app using suggestions from http://flask.pocoo.org/docs/testing/, but I couldn't figure out how to test DELETE method with form data.

My delete method looks something like this:

from flask.ext.restful import Resource, reqparse 
...
def delete(self):
    self.reqparse.add_argument('arg1', type=str, required=True, location='form')
    args = self.reqparse.parse_args()
    ...

I would like to test it with:

def setUp(self):
    self.app = myApp.app.test_client()

def test_delete(self):
    rv = self.app.delete('MyEndPoint', data={'arg1', 'val'})

But it doesn't work. I also looked at the source code of EnvironBuilder in werkzeug.test but still got no idea how to pass in the data.

Answer 1

I just ran into the same issue, and this is basically because Werkzeug's test method does not currently support setting the content_type of DELETE requests.

The code here shows how Werkzeug gets the content type:

def _get_content_type(self):
    ct = self.headers.get('Content-Type')
    if ct is None and not self._input_stream:
        if self.method in ('POST', 'PUT', 'PATCH'):
            if self._files:
                return 'multipart/form-data'
            return 'application/x-www-form-urlencoded'
        return None
    return ct

If there's no content_type, then the form data never makes it out of the environ and into the request, so your Flask server doesn't actually get sent the data.

Ultimately, this is a bug with Werkzeug, as you can craft a curl request that uses a DELETE method and also includes form data. I've submitted a pull request to the Werkzeug repo to address this issue. Feel free to chime in on github: https://github.com/mitsuhiko/werkzeug/pull/620

Update: to actually solve your problem in the mean time, you can get around this by explicitly stating a content type in your request, like so:

def test_delete(self):
    rv = self.app.delete('MyEndPoint',
                         data={'arg1', 'val'},
                         headers={'Content-Type': 'application/x-www-form-urlencoded'})

Update again: The pull request I've submitted has been reviewed, refined, and merged, and will be included in the 0.10 release of Werkzeug, so hopefully this shouldn't be an issue anymore :)