This is examples for the article (in Japasene).
Example 1: Traditional testing with doctest
$ doctest prog1.hs
Examples: 1 Tried: 1 Errors: 0 Failures: 0
Example 2: Property-based testing with doctest and QuickCheck
$ doctest prog2.hs
Examples: 1 Tried: 1 Errors: 0 Failures: 0