FIT [L1 ] is a testing framework originally created by Ward Cunningham "specifically applicable to acceptance tests like those prescribed by Extreme Programming." Its home site is a Wiki where its ongoing development continues.
FIT is also a file format written by some gps devices. "The Flexible and Interoperable Data Transfer (FIT) protocol is designed specifically for the storing and sharing of data that originates from sport, fitness and health devices." for more information see http://www.thisisant.com/pages/products/fit-sdk or to decode the files in tcl see reading fit files