In many survival manuals there are pretty good descriptions about how to build a survival shelter, but something essential is lacking.
And the essential thing that isn't there is an emphasis on testing. Manuals describe what to do in pretty good detail, but they seldom - almost never - stress the importance of putting the things you build to the test, preferably under controlled circumstances because there are many factors that could damage, destroy or turn a shelter ineffective. In some cases this could mean just discomfort, while in others it could literally pose a threat for your survival: you would certainly not want to have to repair or improve your shelter in the middle of a raging storm. It is unpleasant per se but it also means putting yourself in the middle of a risky situation because of slippery terrain, low temperatures, lack of visibility and a lot of things that you tried to avoid by building a shelter that was supposed to be good in the first place.
Having said that, it is important to remember that there isn't a unique recipe for all sorts of survival shelters because these are built using different materials, by people with varying experience and knowledge and so on. You should assume that every shelter will be different and hence, the tests that you will have to perform will also be different. However, you should pay special attention to some areas:
Ventilation, especially if you plan to lit a fire inside your shelter.
Flammability: a fire inside a flammable shelter could produce a disaster in seconds.
Waterproofing: your shelter should provide you effective protection against moisture, rainfall, snow, etc.
Structural characteristics: walls, beams and other elements should be adequate for the kind of protection that you want or need. They should be resistant but also well placed.
As we said, there is no magic recipe for testing all sorts of shelters following a simple, single method. Add to this the fact that lack of experience building survival shelters will likely mean that you will make more mistakes both during construction as well as testing. In other words, even your tests might fail, but on the positive side, you can perform more than just one, so if you don't catch a defect today, you might still catch it the next time you walk around your bivouac looking precisely for defect, problems or shortcomings.
If you take the habit of checking things in your camp often you will be gaining experience and improving your safety, plus, you will see that some problems might arise over time and not be evident from the onset even if you are a seasoned outdoor enthusiast, For example, roof beams or covers could slowly move or slide by cause of rainfall, the weight of snow or the wind; the stones in a wall will settle over time, giving it more solidity but changing angles or positions, thus, things that were assumed to be levelled before, like your main roof beam could suddenly appear to you out of position. Such a change would mean that you would have to test the roof again in order to see if it will still maintain its structural integrity, look for undue pressures or tensions, and to make sure that it remains rainproof.
Perfection is hard to attain in survival shelters; while you build yours you should assume that it will be far from perfect and that there will be issues to correct, even if you are an experienced camper, survivor or survivalist. Your best insurance policy is to be aware of the need of periodic testing, and if you do this right, you will pretty soon enjoy a good, safe and effective shelter. If not, nature will remind you soon enough of your laziness.
Something well-tested before its actual use will perform better,
but even in such cases, like with this survival shelter, tests and checks should be performed periodically to see if water doesn't accumulate in the uneven, soft roof, for example.