How do you write a unit test for a regex pattern?

Question

Is it possible? Would it require a existing whitewashed and/or blacklisted datasets, or not? How would you know an exception did not exist?

possible duplicate of [How do you unit test regular expressions?](http://stackoverflow.com/questions/488601/how-do-you-unit-test-regular-expressions) — Matthew Whited, Oct 20 '10 at 13:03

score 3 · Accepted Answer · edited May 23 '17 at 12:34

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whitelists and blacklists sounds a good approach, I don't think you can "prove" it will work without exception so empirical verification is appropriate and in keeping with the spirit of unit testing

as you think up more complex/edge-case examples to test with, just add them and see if it still works, thus building a test suite in which you have ever greater levels of confidence

also, answered previously very thoroughly here

How do you unit test regular expressions?

edited May 23 '17 at 12:34

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answered Oct 20 '10 at 12:59

Brian

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**@Brian:** Thanks, that's what I thought, just wanted to make sure I wasn't missing something. – blunders Oct 20 '10 at 13:02
np, sometimes it's nice to get a second opinion, so FWIW I would do exactly what you're suggesting – Brian Oct 20 '10 at 13:04

score 2 · Answer 2 · edited May 23 '17 at 10:33

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You might want to look at the following link with an identical discussion that has several good solutions:

How do you unit test regular expressions?
How do you unit test regular expressions?

edited May 23 '17 at 10:33

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answered Oct 20 '10 at 13:01

atconway

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How do you write a unit test for a regex pattern?

2 Answers2