David Rubinstein, of SD Times, has published an excellent editorial entitled “Taking to Testing” in which he summarizes a Web seminar where developer testing was addressed. He specifically writes that the benefit of testing during coding (as opposed to after things are complete)

is more value from the business system being delivered. If ROI is a function of a system’s cost to develop versus the value it delivers to the business, lower development costs translate to higher value.

Well said, Mr Rubinstein.