The Greek dokimion (G1383) refers to the act of testing, the means by which something is tested, or the quality of proven genuineness that results from testing. It is used of the testing of faith — as metal is tested by fire to prove its purity.
Dokimion appears twice in the New Testament, each time linking testing to a positive outcome. James 1:3 — 'the testing of your faith produces perseverance' — reframes suffering as a precision instrument of character formation. Peter compares faith proven by trials to gold refined by fire. The goal of dokimion is dokimos (approved character) — a person whose faith has been proven genuine through trial.