Check those rubber end caps before tearing anything apart. They are, by far, the most common cause of coolant loss in these engines. Make sure you have a good seal on both the tube stack and the manifold tank - particularly check the seal on the tube stack.
You will not see a change in exhaust color (without fluorescent dye and a UV light) if the leak is a cup of coolant per hour - that is a thimble full per minute.
The tube stack is not copper and the design does not have a zinc.
A pressure test will most likely lead you astray into tearing apart and replacing a heat exchanger. If the rubber boots are not set correctly, the pressure test will fail but you will assume the heat exchanger is bad and go about spending a lot of money
and time fixing it for no reason.
Head gasket coolant leaks are the least likely cause of loss of coolant in most engines, and definitely this engine.
I'm not sure why everyone is jumping to a catastrophic failure conclusion when there is a known, simple issue with a coolant system component of these engines.