It's the sort of testing that goes on with the computer equipment as well.
Image a high-end graphics workstation with the latest Intel, PowerPC and/or NVIDIA chips - your dream gaming machine. Then get it to work via board edge cooling only - fans are a complete no-no. Then get it to start up at -55C and stay working when the ambient temperature reaches +85C (or visa-versa). Then shake it like hell. All in a card the size of a mobile phone. Welcome to the mil-aero-space world :-)
The main UK manufacturer of this kit is Abaco Systems - it's US rival being CW