Yard Light, or Post light
Most problems I have found with outside lights like this are at the pole itself.
Where to look, where the wires come up or are spliced or the fixture itself.
In the case of trying to do a continuity test here don’t waste your time a tester or ohm meter is low voltage and will not find the fault in most cases.
Remove the lamp and if it has a motion sensor remove that. Turn the circuit on and see if it trips the breaker if not put a new fixture / motion sensor in, if it still trips I dig up the lamp pole, at the bottom or in the pole is the next most common place.
If the breaker is tripping with the pole disconnected the only other way is a tracer to find where the wire was cut or insulation damaged.
2800 sounds a bit high but trenching and going under sidewalks (finished basement?) all takes time to get a new feed to the pole so I would be checking that out trying to isolate the short before having it replaced because in my experience it is usually at the pole. Or damaged by digging but that can be repaired for a couple hundred bu a electrician or 50$ DIY if the cut is identified.