In a dusty or sandy enviroment, in a very dry and a very humid environment, under direct sunlight, in cold and hot temperatures, drop them from table-height, bang them inside a carry case, smash the buttons with your fingers...
Hot and sandy conditions. Many military in the middle east use tough books and such for their computing needs and it would be of great help to see which laptops would hold up the best before making an investment your stuck with for a year.
1) put in backpack naked (no books as book is padding). drop it from shoulder height
2) same as #1 but drop it around 10-12 ft high
3) put in backpack naked, bang it against a metal pole like flag pole
4) put in backpack naked, pour small amount of soda on the backpack
5) same as #1 but pour a whole can of soda on the backpack
6) put laptop on stable table, drop a commercial-grade screwdriver directly on top (don't throw, just drop)
7) same as 6) but use commercial-grade hammer
8) do 6 and 7) with laptop open
9) attach the power cord, tie the cord to a truck and drive the truck 10-20 mph for 10 seconds
10) repeat 9) but continue at 25-35mph for another 10 seconds
11) summon God and have Him break it
gotta have drop testing, and it has to be repeatable. One drop on each side, notation of visual damage. This should be done while the laptop is on. I think a good torture test would be to drop a laptop down the stairs and should ensure that it gets beat from about every angle, though its not entirely repeatable.
I use my notebook for astrophotography. It has to be able to stand up to extremes of heat and cold, moisture (in the form of dew), dust, dirt and quite a bit of rough handling. My Toshiba Satellite x205 has held up very well. I've even smooshed a few mosquitoes on it and the screen cleans up very nicely
1. Drop tests, from the hood of a pick up truck.
2. Sand, dirt, mud, on the keyboard, screen, can the dirt get inside? Use a fan to blow some of the dirt around.
3. Put inside a car, while on, and drive on a bunch of rocky, bumpy, roads and see if it still works.
4. WI-FI strength, can they still connect to the construction trailer while looking at things outdoors.
5. How well can you read the screen in sunlight?
6. Battery life? How long to charge? How easy to swap out battery?
7. Can the laptop be used to detonate the charges to blow up the building?
Leave it in a dusty wood working shop and see how long it runs before it overheats.
Drop it, tip it! Lots.
Leave it in the sun for a week. With the screen open.
Spill coffee on the keyboard. Then clean it using only windex and toilet paper.
As an EMS agency, we use rugged laptops for patient care reports.
1. Drop from stretcher height.
2. Use it in the rain (water exposure in real world use)
3. Expose to cleaning solutions (to wipe away various fluids, etc)
4. Repeated key presses.
5. If it has a touch screen use a stylus on the screen in a up/down or side/side motion (i.e. scrollbars) repeatedly to see about screen wear.
As mentioned above, drop tests to start with. After that, you definitely need to test it in the rain, sand, mud, etc. I would also try bending it (i.e. hold the sides tight and press on the middle). It would also be interesting to see if it worked while submerged...