Hard to beat a lightning direct effects high energy test for deliberate electrical Ka-Boom with uncertain outcome.
The ultra high voltage attacnment and isolation tests look impressive but they don't blow the test item apart (and sometimes through the roof, literally) like the high energy tests.
Typically 3 parts to the applied test current. It starts with 200,000A for 500us with a 50us 10% to 90% rise time (3200A/us). Then 2,000A for 5ms followed by 200 coulombs in 0.25s to 1s at 200A to 800A.
First two are capacitor discharge, last was historically a big bank of commercial vehicle batteries but some people now use big DC power supplies.
That line about blowing things through the roof reminds me of the "Hazardous Procedures Laboratory" in the chemistry department at university, which was literally a wooden prefabricated garden shed constructed on the flat roof of the Chemistry/Biology building. Instead of being bolted together at the various junctions as the manufacturer intended, the bolt holes just had loops of baling wire that was twisted together, to allow *ahem* 'rapid disassembly' while keeping the panels intact. Most people who saw it thought it was the biologists growing something, probably pot knowing the average biology student.
On the latter note, some years back when the Laboratory of the Government Chemist was still in central London on the corner of Waterloo Bridge Road and Stamford Street (it's now on the NPL site in Teddington), if you looked carefully you could see a large glass greenhouse on the roof. That
was used to grow pot, officially. Also probably officially secretly but as it's not there now I think I can risk publically mentioning it without getting my door kicked down by government goons. They didn't rebuild the greenhouse when they moved to Teddington, so BD, it isn't worth scaling the NPL perimeter fence in hope of scoring some government grade marijuana.