quickcheck Questions
3
The QuickCheck library seems to catch all exceptions that are thrown when testing a property. In particular, this behavior prevents me from putting a time limit on the entire QuickCheck computation...
Swept asked 3/3, 2012 at 21:48
3
Solved
One should think that this is a FAQ, but I haven't been able to find an answer to this simple question:
Which version of a certain package do I have in my GHC installation?
Background
I'm trying...
Aerophobia asked 25/11, 2015 at 10:29
2
Solved
I have two functions. They are:
f1 [] = []
f1 (x:xs) = if contains x xs then f1 xs else x:f1 xs
and
f6 xs = f1 (rev xs)
It would not make sense that these two functions return the same list for a...
Oxidize asked 26/5, 2021 at 23:30
2
Solved
My ghci version is 8.4.3
I tried
stack install QuickCheck
Something was installed. But when I input import Test.QuickCheck, it tells Could not find module ‘Test.QuickCheck’ again. How can I fix...
Gaucherie asked 20/11, 2018 at 22:3
3
I'm working through the wonderful Haskell Book. At the end of the Traversable chapter (21), I need to write an instance for the following Tree:
data Tree a =
Empty
| Leaf a
| Node (Tree a) a (Tr...
Canady asked 1/1, 2021 at 19:56
2
Solved
I'm getting an error that says the module doesn't exist when I try to runhaskell. It's odd because I try to install it first and says its up to date. Any idea how to fix this?
Unmeriting asked 10/9, 2020 at 20:57
1
Solved
I'm using QuickCheck to generate arbitrary functions, and I'd like to generate arbitrary injective functions (i.e. f a == f b if and only if a == b).
I thought I had it figured out:
newtype Injec...
Newsmonger asked 25/5, 2020 at 3:6
2
Solved
Why isn't there a QuickCheck function similar to hedgehog's success? In particular I was wondering how one could translate a property like the following one:
prop_specialPair :: Property
prop_spec...
Voluntarism asked 17/12, 2019 at 22:41
4
I have a Haskell data type like
data Mytype
= C1
| C2 Char
| C3 Int String
If I case on a Mytype and forget to handle one of the cases, GHC gives me a warning (exhaustiveness check).
I now w...
Degauss asked 27/8, 2014 at 19:36
1
Solved
I'm looking at the comments in shrink:
It is tempting to write the last line as [Branch x' l' r' | x' <- shrink x, l' <- shrink l, r' <- shrink r] but this is the wrong thing! It will f...
Epergne asked 24/9, 2019 at 6:42
2
Solved
Using QuickCheck, I'd like to create a series of pseudorandom TimeOfDay values.
It's easy to create a specific TimeOfDay:
now = TimeOfDay 17 35 22
Printing this with GHCi 8.6.5 yields:
17:35...
Suspensor asked 8/9, 2019 at 15:58
0
I'm using QuickCheck to test automatically-generated properties (similar to QuickSpec) but one common problem I'm running into is exhausting the memory, either due to naive recursive generators or ...
Buyer asked 24/4, 2019 at 12:58
3
Solved
I'm trying to get started with Haskell's QuickCheck, and while I am familiar with the concepts behind the testing methodology, this is the first time I am trying to put it to use on a project that ...
Rochette asked 20/9, 2018 at 21:40
4
Solved
What is the best practice to display reasons for a failed property test when it is tested via QuickCheck?
Consider for example:
prop a b = res /= []
where
(res, reason) = checkCode a b
Then t...
Eufemiaeugen asked 23/1, 2011 at 8:17
1
Solved
I build the initial codebase for my Haskell project with cabal init
I have several tests written with Hspec.
On cabal test it compiles and runs these tests like expected and gives a message for fai...
Fullblooded asked 30/7, 2018 at 11:45
2
Solved
I was trying to write a QuickCheck test for the identity
f $ y = f y
My initial plan was to write an arbitrary generator that returns functions & Integer, having the signature Gen (Int ->...
Bracer asked 31/5, 2018 at 17:43
4
Solved
Is there a version of quickcheck that works for Javascript and that is well maintained? I have found several such as check.js and claire, but none of them seem to support shrinking of failing test ...
Pimple asked 12/5, 2014 at 11:39
3
Solved
tl;dr: how do you write instances of Arbitrary that don't explode if your data type allows for way too much nesting? And how would you guarantee these instances produce truly random specimens of yo...
Crapulent asked 11/4, 2013 at 21:40
2
Solved
I have a set of simple demo programs which encode/decode strings, and want to generate some quickCheck tests for them, but to limit the tests to printable strings only. Using a guard is too slow an...
Sphygmic asked 5/1, 2014 at 14:7
1
Solved
I am working through the Haskell Book and have come to the point of writing an Arbitrary instance for newType Comp. The code is below
instance Show (Comp a) where
show f = "Unicorns!!"
newtype C...
Dihedron asked 16/12, 2017 at 19:49
0
How do I use the checkers library to test the Functor laws of a simple Parser?
import Test.QuickCheck
import Test.QuickCheck.Checkers
import Test.QuickCheck.Classes
import qualified Data.ByteStri...
Margaretemargaretha asked 19/11, 2017 at 12:57
1
Solved
From Doctest's readme, one can use doctest with QuickCheck, like this:
-- |
-- prop> sort xs == (sort . sort) (xs :: [Int])
I would like to describe this property using multiple lines, probab...
Fruitful asked 15/6, 2015 at 3:20
1
Solved
I just migrated a pytest test suite from quickcheck to hypothesis. This worked quite well (and immediately uncovered some hidden edge case bugs), but one major difference I see is related to test i...
Cowfish asked 30/8, 2017 at 9:26
2
Solved
There is the forAll quantifier that returns a property which checks if all test cases pass. Is there a way to define a "there exists" quantifier that returns a property which checks it at least one...
Interdenominational asked 13/3, 2017 at 13:28
1
Solved
I could use a complete example of how to use quickCheckAll. Here's what I've tried so far:
In a file A.hs:
module A where
import Test.QuickCheck
prop_a = 1 == 0
check = do
return []
$quick...
Temekatemerity asked 8/3, 2017 at 10:41
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