Update tests for new serialization methods
Update tests for new serialization methods

rcrowder/pycapnp,SymbiFlow/pycapnp,jparyani/pycapnp,rcrowder/pycapnp,tempbottle/pycapnp,SymbiFlow/pycapnp,SymbiFlow/pycapnp,jparyani/pycapnp,tempbottle/pycapnp,rcrowder/pycapnp,tempbottle/pycapnp,rcrowder/pycapnp,jparyani/pycapnp,jparyani/pycapnp,SymbiFlow/pycapnp,tempbottle/pycapnp