I posted some time ago a load of terms and definitions here's the acetate and test press bits.....
Acetate/Lacquer
Is usually a reference cut that is made on ultra high-grade methyl cellulose
sprayed onto thick aluminium discs. Reference acetates are primarily to make
certain the record will sound somewhat like the tape. Often they are also
made to allow a club or radio disc-jockey to play the music on turntables
before it has been pressed as a normal record. Acetate is a misnomer. It is
actually a Lacquer, but since so many people call these acetates, both will
be used here.
Test pressing A test pressing is sent back to the cutting engineer, producer and
sometimes the performer, to confirm that the pressings will sound as
intended. Most TP's are really just early pressings, frequently without
artwork of any kind, and they are serviced to whoever as early promo's. In
many cases this was done to rush the record out to radio stations to try and
get immediate airplay before the complete label could be finished.