Tst-drvn dvlpmnt (TDD) s wy f wrtng cd tht nvlvs wrtng n tmtd nt-lvl tst cs tht fls, thn wrtng jst ngh cd t mk th tst pss, thn rfctrng bth th tst cd nd th prdctn cd, thn rptng wth nthr nw tst cs.
ltrntv pprchs t wrtng tmtd tsts s t wrt ll f th prdctn cd bfr strtng n th tst cd r t wrt ll f th tst cd bfr strtng n th prdctn cd. Wth TDD, bth r wrttn tgthr, thrfr shrtnng dbggng tm ncssts.
TDD s rltd t th tst-frst prgrmmng cncpts f xtrm prgrmmng, bgn n 1999, bt mr rcntly hs crtd mr gnrl ntrst n ts wn rght.
Prgrmmrs ls pply th cncpt t mprvng nd dbggng lgcy cd dvlpd wth ldr tchnqs.