Do a search on Wiki for the origin of 'testify' (as in court) and you may begin to share my enthusiasm, lol.

Sorry to dispel a favorite misconception, amusing as it may be:

testis (n.) Look up testis at Dictionary.com

(plural testes), 1704, from Latin testis "testicle," usually regarded as a special application of testis "witness" (see testament), presumably because it "bears witness to male virility" [Barnhart]. Stories that trace the use of the Latin word to some supposed swearing-in ceremony are modern and groundless.

http://www.etymonline.com/index.php?term=testis&allowed_in_frame=0