Just a heads up for everyone: this test is EXTENSIVE.
There are 3 separated test. The first one runs 30 minutes, the second for an hour, and the last for 6 hours. My console is connected wirelessly via the N adapter, however I'm not experiencing any network slowdown on my main desktop (that's hard wired)--so I guess if you want to turn your console on, run the tests and come back later--you shouldn't experience any slowness on any other computers on your network.
I kind of thought it was ironic that Microsoft trusts their consoles enough to be left on for 7.5 consecutive hours.