>I say this because two days ago I wrote a test that used all country codes as input. It took 15 minutes to write that test. During the whole testing session I found at least 5 mistakes of which 3 would have been quite dramatic.
And how many minutes to test all city/state/region/street/person names ?
It can also happen that you test s will become outdated, like when url standard changed and more characters codes were allowed.
For something like URLs I'd use the hypothesis Python module and rely on their implementation of URLs (and if that changes the test will fail for newly formated URLs), for everything "custom" I would extract problematic test cases and include them as examples.
Testing doesn't take too long on my machine (maybe 10 seconds), but even if it would, it would be totally acceptable as I run it pre commit only.
And how many minutes to test all city/state/region/street/person names ?
It can also happen that you test s will become outdated, like when url standard changed and more characters codes were allowed.