There are several good tests described in Tests for Bufferbloat.
The two most convenient scripts I regularly use are easily downloaded and continue to be maintained by @richb-hanover.
- betterspeedtest.sh emulates speedtest.net (download, then upload)
- netperfrunner.sh emulates FLENT (simultaneous download/upload)
Having an OpenWRT/LEDE package that simply included these would be handy for many I imagine.