Engines can also use the fuel as a servo(muscle) force on a lot of components driving them to the commanded position via a touque-servo motor.
These components when replaced require a leak check without the engine running so a 'wet-crank' is performed. These servo lines are tapped off before the main fuel shut-off valve. The trick is to get the fuel to the engines without flooding the combustor chamber as the LP valve is usually linked in series with the HP valve from the Master switches.
Pulling a circuit breaker as previously mentioned can fail safe the LP valve open whilst keeping the HP valve closed. The components can be leak checked or in the case of the Airbus CFM the FADEC can perform a full function check.
Airbus engine run check list has all the scenarios I perform on a daily basis including wet and dry cycles, but I do not hold an electronic copy of this manual, maybe somebody could help Obi with this???