QuickCheck is a Haskell library for software testing. It generates test cases and validates them against assertions provided by the programmer.
Questions tagged [quickcheck]
422 questions
0
votes
1 answer
Generate choose on custom data type with 2 options
I am trying to achieve something very simple.
I have this data type :
import Test.QuickCheck
import System.Random
data Letter = G | B deriving(Show, Eq, Bounded)
arbitraryLetter :: Gen Letter
arbitraryLetter = choose (G,B)
I am compiling and…
Eyzuky
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0
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1 answer
`No instance for System.Random.Random` on a custom typeclass when using `choose`
I am doing an exercise in Haskell Programming from First Principles. It asks me to generate equal probabilities, and 1/3, 2/3 probabilities from each of:
data Fool =
Fulse
| Frue
deriving (Eq, Show)
And my answer is
module Random where
--…
cmal
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0
votes
1 answer
Hspec & QuickCheck - Ambiguous type variable a0?
I have written a function in Haskell that takes a list of arbitrary elements and returns (mapped) a list of tuples. Each tuple contains the original element and a fraction, with all the fractions in the list adding to 1 (therefore I simply calculate…
Raiden616
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0
votes
1 answer
QuickCheck Haskell - generating random lottery tickets
This works :
genAnimal :: Gen String
genAnimal = do
animals <- shuffle ["tiger","rabbit","dragon","snake","rat","ox","pig","sheep","horse","monkey","dog"]
return (head animals)
genWinner :: Gen String
genWinner = do
animal <- genAnimal
…
Cliff Stamp
- 531
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0
votes
1 answer
How to quickCheck on custom ADT in PureScript?
For using QuickCheck, I'm trying to implement the Arbitrary instance:
import Test.QuickCheck
import Test.QuickCheck.Arbitrary (class Arbitrary, class Coarbitrary)
data Arith = Lit Int | Add Arith Arith | Neg Arith
derive instance arithEq :: Eq…
luochen1990
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0
votes
1 answer
Could not find module ‘Test.QuickCheck’ on Mac
When I try to test my code, IntelliJ gave me this error. However, I have used cabal install QuickCheck to install.
Testing.hs:3:1: error:
Could not find module ‘Test.QuickCheck’
Use -v to see a list of the files searched for.
|
3 | import…
K3大魔王
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0 answers
In Yesod.Test, is it possible to get into `SpecM (TestApp site)` from `IO`, similarly to how `liftIO` allows the opposite?
More specifically, I'm looking for a function of type:
f :: site -> SpecM (TestApp site) b -> IO b
or similar.
In other words, I am looking for the inverse function of:
liftIO :: IO b -> SpecM (TestApp _site) b
I've looked in the Yesod.Test docs…
Wizek
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0
votes
1 answer
"Gave up" - QuickCheck
I want use quickcheck in a function that tests if a Maclaurin series is equal to 1/x, for x>1 and x<2. However, for small values of n, quickcheck returns false tests. Additionally, if I put n>100 restriction, for example, quickcheck returns:
"Gave…
89 Juan
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- 1
0
votes
1 answer
How to generate test data with shuffle in QuickCeck
For a given list [1..n], where n is a random positive integer, I want to generate the test data with 2 steps:
Shuffle the list, xs = shuffle [1..n];
Random mutate a number x in xs to y, where 1 <= y <= n;
After these 2 steps, the new list is…
Larry LIU Xinyu
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0
votes
1 answer
Defining a property in haskel locally
I have written this property check in haskell:
prop_XY (x,y) sud = ((!!) (rows (sud)) x) !! y
and i need to define this locally, any suggestions on how to do it as i am clueless how to do it?
EDIT
So this is the two prop functions i have, and i…
Timo Cengiz
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0
votes
1 answer
"[(),()]" array in Haskell
Recently, I've been doing automatic testing with Haskell and QuickCheck. Some time I have got some fails, but the program retrieved [(),()] as checked argument.
What does "[(),()]" mean?
fant0me
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0
votes
1 answer
Haskell GHC: Failed to load interface for 'Test.QuickCheck'
So I have to include the 'Test.QuickCheck' library for some testings for a subject. Although I've use it the whole year, I reinstalled GHC/GHCi recently and it doesn't load this library. The other functions work as planned. Currently using Xubuntu…
fant0me
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0
votes
1 answer
Generating random strings from a string-pool using QuickCheck
Consider the problem of generating strings out our a set of possible strings, in such a way that once a string is chosen, it cannot be repeated again. For this task I would like to use QuickCheck's Gen functions.
If I look at the type of the…
Damian Nadales
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0
votes
1 answer
Testing 'DAG' aka acyclic graphs properties in Haskell QuickCheck
module Graph where
import Control.Monad.State
import Data.Maybe
import Data.Set as Set
-- | 'Edge' represents an edge entre two nodes.
data Edge v = Edge {source :: v, target :: v}
deriving (Show,Eq,Ord)
data Graph v = Graph {nodes…
Fluids
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0
votes
1 answer
Haskell Generating graphs with QuickCheck properties
Graphs have these properties:
The type 'Edge' represents an edge between two nodes.
data Edge v = Edge {source :: v, target :: v}
deriving (Show,Eq,Ord)
The 'Graph' type represents a directed graph.
data Graph v = Graph {nodes :: Set v,…
Vinho
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