Refactor the string generation to be done by testing methods.

Change-Id: Ic6a2d768acdc44604b01d2948a8c7bfae54f6bce
Verify that the zero copy constructor for JobContent works.

Also add code to verify that the contents of the data after serialization
is bitwise identical.

Change-Id: I8c19cf04d774e38da46008a87cddf9f456a1bb58