Throughput testing can be done in a number of different ways:
Fast.com - This is a Netflix speed test, which is executed using headless chromium and the fast.com website
Dropbox - This makes use of the dropbox API to upload and download a file (the size of the file can be specified in the test configuration)
YouTube - A YouTube throughput test can be performed, which involves downloading a video from YouTube’s CDN
iPerf3 - If you have an iPerf3 server you can configure sensors to test against these servers
Librespeed Test - Librespeed testing is similar to iperf3 but you will have plenty of public Librespeed servers available to choose from for testing.