A far better way is to do a voltage drop test under load
If it under 200 millivolts your good to go and move on
Jump leads are hit and miss in my opinion, getting a good connection on a rusty block is harder than you imagine, if your stuck in the middle of nowhere, yes it will get you going again, often takes several attempts at getting a good connection when jump staring a car and that's if you are using the relatively easy battery connections not the blocks
Seen several failures of this method, putting the jump leads on the lifting eye is quite common, they are painted and isolated from the block, yes I have fallen into this trap myself
I have a good example on a Suzuki alto here at the moment where someone has tried to fix a bad earth and failed, they have cleaned the earth strap eye but have not cleaned the rusty block it's bolted to
I will post some picture of voltage drops testing later today and link them here
