Disclaimer: This has been hacked together in about an hour. speedtest-cli is hard-included which is not very clean. Feel free to contribute.
- Obtain OAuth2 credentials from Google Developers Console
- Replace 'google.json' with the json file optained in step 1.
- Save a copy of the Template google document as 'Speedtest' to your account and grant write access to the service account you created in step 1.
- Install gspread
- Add the script to cron or run it manually.