There are two types of programs that might be what you are looking for. The first would be a diagnostic utility that is meant to specifically test the various systems of the laptop. The other would be a benchmark or stressing program that basically exercises the hardware and tells you how fast (or slower) your system is compared to others. There's no software that I know of that would directly test for "soldering defects".
One of the better diagnostic programs is what was originally supplied by Lenovo: PC Doctor for DOS. It is meant to be run from a bootable CD (meaning you don't even need a hard drive or operating system). It is designed to test almost all of the hardware systems: CPU, memory, hard drive (and interface), CD/DVD, video (GPU), audio system, I/O ports (ethernet, wireless, serial, parallel) keyboard/mouse/touchpad. However, this program is not freely available from the factory ever since Lenovo cancelled their contract with PC Doctor. The version for the X200 is named 7tt123ww.
ref:
http://forum.thinkpads.com/viewtopic.php?f=18&t=105918
There are other diagnostic programs meant to test only a certain part of the system: memory and hard drive being the common ones. For memory, I like to use memtest86+. Hard drive manufacturers usually supply a diagnostic that tests their own hardware: SeaTools for Seagate drives, DFT (Drive Fitness Test) for HGST/Hitachi/IBM drives, etc.
The second type of program is like 3DMark Vantage (which from what I understand only tests the video section of the computer). Overclockers like to use Prime95 to stress test the CPU and memory.