Conversion of curl to python Requests
Your server is expecting JSON, but you aren't sending it. Try this:
import requests
import json
payload = {'query': json.dumps({"tags":["test1", "test2"]})}
url = 'http://www.test.com/match'
r = requests.post(url, data=payload)
if __name__=='__main__':
print r.text
There is an open source cURL to Python Requests conversion helper at https://curlconverter.com/. It isn't perfect, but helps out a lot of the time. Especially for converting Chrome "Copy as cURL" commands. There is also a node library if you need to do the conversions programmatically