The very best way to test the ground or positive circuits is a voltage drop test.
Set your multimeter to 12 volts DC. Connect one lead to your neg. battery post (not the battery cable terminal) connect the other end to a clean bolt or such on the engine block. Now have someone try to start the car while you watch the meter. Any reading of less than 10 percent of 12 volts or 1.2 volts is acceptable and tells you the tested circuit is good. This test works the same for the positive side also. So if your ground side tests good do the same test from positive battery post to starter lug. Just remember to hook your meter to the battery post and the starter cable bolt, not the battery terminal or terminal that hooks to starter and the circuit must be energized.