Hello Han On 11-06-21 17:16, Han Joosten wrote:
[..] *parseFoo :: Text -> Guarded Foo* *prettyFoo :: Foo -> Text*
The idea is that for all foo :: Foo, the following holds: *parseFoo . prettyFoo $ foo* should be equal to *Checked foo []*
Now, if there is a counterexample, I would like to see prettyFoo foo as output, folowed by the show of the Errors part.
It seems you know what property should hold for `parseFoo` and `prettyFoo`. Per the QuickCheck manual [1] this could be written as import Test.QuickCheck propOnAllFooText :: Property propOnAllFooText = forAll (arbitrary :: Gen Foo) $ \exFoo -> parseFoo (prettyFoo exFoo) == Checked exFoo [] What you are missing is a way to generate the test cases (the `arbitrary' generator above). You need a way to declare this instance instance Arbitrary Foo where -- arbitrary :: Gen Foo arbitrary = <something> You can see example on how to define it on the manual [1]. Good luck. [1]: http://www.cse.chalmers.se/~rjmh/QuickCheck/manual.html -- -- Rubén -- pgp: 4EE9 28F7 932E F4AD