When I worked at a bike shop in the late 70's, bikes used to come in a crate with the font wheel and handlebars removed. All you needed to do was slip the wheel in, bolt on the bars and fit the controls, switches etc. Fill the battery with acid and connect it up.
Despite this, we used to give every bike a dummy MOT and complete spanner check. Spike the mechanic also stuck the strobe light on them to check the timing was ok.
A gallon of petrol, check the oil and tyre pressures and a run round the block. As the shop was in a village in Staffs 'the block' had some lovely bends
We never found much wrong (we were Suzuki dealers after all) but we didn't get any pdi comebacks either.