when a time it estimated for a usecase it should contain the dev test  effort as well. if 5 days is not enough, then the view on that UC must have been very optimistic or a step has been missed. but test should be considered in uc estimate effort.

DAOs are part of a uc or couple of UCs, the test that you write depeneds on the uc, no one here can tell you how much time you need to add to the estimate effort to include testing, that really depends on the uc but definitely will increase the dev time. usually (considering one process) there is at least unit test & functionality test involved in each single uc, but again that is case by case basis

estimating time on a uc, depeneds on the vision on the particular project, experience on similar projects and also the parameters of the type of process involved in development