Re: What is the difference between a corner case and edge case? (boundary count)

An edge case is where the program logic meets a boundary condition. A corner case is where you meet more than one boundary condition at once.

Edge cases are things you should test for in your unit tests because they are a very common place for bugs to be. Corner cases are usually talked about in terms of "I found a bug, but it is a bit of a corner case so it might not be worth fixing", that is, it will be encountered very rarely.

- tye

Comment on Re: What is the difference between a corner case and edge case? (boundary count)

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Re: Re: What is the difference between a corner case and edge case? (boundary count) by graff (Chancellor) on Jan 14, 2003 at 06:30 UTC
Based on this first paragraph: An edge case is where the program logic meets a boundary condition. A corner case is where you meet more than one boundary condition at once. I'm tempted to supplement the second paragraph with: Corner cases may also be ones that seem impossible when they actually are encountered, which in turn consumes a lot more time in the fixing (due to a larger number of false-starts and irrelevant quadruple checks when debugging), and ultimately causes the hardest forehead-slapping once they are finally solved, as in "who would have thought that these two simple, unrelated conditions could have produced such a bizarre result???"	[reply]
Re^2: What is the difference between a corner case and edge case? (boundary count) by Aristotle (Chancellor) on Jan 14, 2003 at 10:35 UTC
Thanks! I had been using "corner case" to mean "edge case" so far without even knowing about the latter. Terminology is very important to me, so your excellent clarification is much appreciated. Makeshifts last the longest.	[reply]