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How much testing is enough?
By Kathleen Melymuka
Managing, Aug. 17, 1998 Don't let the auditors and lawyers spook you into trying to test every system.
You don't have the time — and it isn't necessary.
"Nobody will be able to test at 100% coverage, but I don't know why anyone would really want to do that," says Matt Hotle, a research director at Stamford, Conn.-based Gartner Group, Inc.
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Three levels of year 2000 testing
Regression testing: Checks software that has been fixed to ensure that no new errors have been introduced.
Forward-date testing: Checks whether software performs properly by using various future dates such as Jan. 1, 2000; Jan. 3, 2000; Feb. 29, 2000; and so on.
Integration testing: Checks whether remediated systems work together properly throughout a department, division, company or among business partners.
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There comes a time when it makes good business sense to stop testing, says Boris Beizer, a senior consultant at Cutter Consortium in Arlington, Mass.
"Every potential failure has a cost," he says. "We stop remediation and testing when the expected gain of further effort is less than the cost."
Even mission-critical systems don't need to be tested to death. Hotle suggests that you dig down into the applications, find the functions and transactions within those programs that are truly critical pieces and test only those.
For example, a mission-critical billing system might include functions that you can't live without, such as invoice generation. It also may include functions you can live without, such as report generation. So test the invoice function rigorously and lay off the reports function.
That's just what Randy Bauer is doing. "We're not testing the use of every piece of data and every system; that would be impossible," says the program manager for the year 2000 project at Toyota Motor Sales USA, Inc. in Torrance, Calif. "We're beginning to focus selectively on mission-critical functions."
Your application experts — the people who developed the system or know it best — can help you separate critical functions from noncritical. Don't set yourself up for failure by attempting to do the impossible.
Hotle asks when Microsoft last delivered defect-free software. "But it's good enough for the marketplace, and that's what you should be aiming for," he says.