I cannot seem to find a way to use the test source to find either Vtest or Itest. Can anyone tell me if I have to turn off all independent sources? or do I use the test source method when there are no independent sources?

 

You don't HAVE to turn off the independent sources, but it sure makes life a lot simpler. If you don't turn them off, then you have to isolate how much of the test signal is due to the test source and how much is due to the other independent sources. You can do this by looking for R = dv_test/di_test.