For a verification that I was recently working on we tried very hard to make sure the verification was written in a way that deviation could be avoided. We attempted to run the test ourselves as well as making sure that our product was perfectly configured and our test samples did not contain any errors. With this there is a still a large risk that a deviation will need to occur. The proper planning prevents this from being a definite as the deviation will be significantly more time consuming than if the verification is able to work as intended the first time. Also a CAPA will not need to be written if a deviation does not occur so it will also save time in that aspect as well.