If one of the Yanomami people of the Amazon basin (yes they still do it the old fashioned way) were to be asked, he would likely tell you that if the Bowyer didn't say the proper prayers over the wood while shaping it the bow would be useless. His practical experience tells him that those prayers are a necessary part of building a proper bow, the technical testing would likely come in the forest where he would attempt to bring down a Tapir or other game. Failing to kill on the first attempt or on successive attempts would find him back at the Bowyer demanding additional prayers.
Not much has changed in the thousands of years bows have been in production. The engineer/village bowyer design and build them, the end user blames all failure on the engineer/bowyer and demand additional prayer.