So regards logging from SO and other sites on the Internet the best response seems to be:
void DoSomething() {
Logger.Log(\"Doing something!\");
// Code.
Personally, I practice TDD/BDD pretty religiously and I almost never test logging. With some exceptions logging is either a developer convenience or a usability factor, not part of the method's core specification. It also tends to have a MUCH higher rate of change than the actual semantics of the method, so you wind up breaking tests just because you added some more informational logging.
It's probably worthwhile to have some tests that simply exercise the logging subsystem, but for most apps I wouldn't test that each class uses the log in a particular way.