A leakdown test is more revealing than a compression test. All you need is an air compresser and hose, if your engine uses 14mm plugs the hose fitting will screw right in the plug hole. Listen at the intake, exhaust, rad cap and crankcase ventilator to find where the air is going.
Smell the smoke, too. A leaking head gasket smells sweet, a scored wall or piston has a scorched smell.
Smoking on one side is usually a head gasket or cracked head, or leaking intake gasket.