I think you refer to E-GPRS technology, right ? Or is it 3G ? I recall 3G is using PDP contexts as well ? It should…
Anyway, to perform such test, you need either a drive-test mobile (such as TEMS or NEMO, google them), or any recent phone that you could use as a modem towards your computer.
Your computer would be connected to internet through the wireless data connection (2G or 3G).
Then, from the PC, do some downloads and pings to your GGSN or near-by servers. And then dowloads and pings to internet servers….