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
Functor laws checking with QuickCheck-classes library
I want to check functor laws for instance:
instance Functor Stream where
fmap f (x :> xs) = (f x) :> fmap f xs
where Stream is
data Stream a = a :> Stream a
I use QuickCheck.Classes (http://hackage.haskell.org/package/quickcheck-classes) to…
Alimagadov K.
- 175
- 2
- 7
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2 answers
Is there any ways to traverse a random json string created by a generator in java?
I have a generator which is generating a completely json scripts with random keys and values(quickcheck.generator). I want to read this string and get the values of the keys. The problem is that each time, a new json string is creating with…
Mahdis Ghaffarian
- 53
- 5
0
votes
1 answer
quickCheck returns error when comparing zipWith functions
I created my own myzipWith function and want to compare it with the original zipWith with the use of quickCheck.
myzipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
myzipWith a y [] = []
myzipWith a [] y = []
myzipWith a (x:xs) (z:zs) = [a x z] ++…
Parviz Ahmedov
- 23
- 7
0
votes
1 answer
Is there any way to generate values for testing this way in Haskell QuickCheck?
I have 2 data types that I use for the representation of natural numbers in the unary system
data Valoare_Unar = Unu deriving(Show);
data Numar_Unar = Invalid | Unar [Valoare_Unar] deriving(Show);
I have those functions for converting this number…
mariciucioan
- 15
- 6
0
votes
1 answer
How to test functions that assume their inputs come from smart constructors?
tl;dr
I'd like to understand how to use Test.QuickCheck to test functions whose arguments are passed to smart constructors and/or assumed as coming out of a smart constructor.
Long version
In a module I have a user defined type like this:
newtype…
Enlico
- 23,259
- 6
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- 102
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1 answer
Why does QuickCheck take a long time when testing a Functor instance with a specific type signature?
I'm working through the wonderful Haskell Book. While solving some exercises I ran QuickCheck test that took a relatively long time to run and I can't figure out why.
The exercise I am solving is in Chapter 16 - I need to write a Functor instance…
javinor
- 674
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- 8
0
votes
1 answer
python-quickcheck: error fixture not found
I'm trying to use the python-quickcheck library, and I just wrote a super simple test inspired by the official documentation:
#!/usr/bin/env python3
import pytest
@pytest.mark.randomize(min_num=0, max_num=2, ncalls=5)
def…
tobiasBora
- 1,542
- 14
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0
votes
1 answer
How to generate hidden instance for data field which type is Generic
I looking for a safe way to generate instance for a data type
which has fields without a deriving class, but such fields have
Generic instance.
I think it is very popular case for testing with QuickCheck,
cause every type should have…
Daniil Iaitskov
- 5,525
- 8
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- 49
0
votes
1 answer
QuickCheck Arbitrary instance for abstract data type with smart constructor
I am new to the language, trying to write my first non-trivial program. On the way, I am stuck creating an Arbitrary instance. Yet, I suppose my question to follow points at my general lack of understanding composing several applicative and monadic…
Ulrich Schuster
- 1,670
- 15
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0
votes
0 answers
QuickCheck property with type [Int] -> Property
I'm very new to QuickCheck. I know how to write QuickCheck properties like :
prop_rev_involutive l = (reverse $ reverse l) == l
that test the reverse function.
But now I need to write a QuickCheck property with this signature…
Tomer
- 1,159
- 7
- 15
0
votes
0 answers
Using QuickCheck for testing if a list is shuffled
I need to use QuickCheck to check if a list of integers is truly shuffled
prop_fastShuffle_correct :: [Int] -> Property
prop_fastShuffle_correct s = ???
My shuffle function has this signature:
fastShuffle :: [a] -> IO [a]
No need to go for full…
Tomer
- 1,159
- 7
- 15
0
votes
1 answer
Haskell QuickCheck generating values within a function
How do I get this contrived example to work?
newtype Q = Q [Int]
instance Arbitrary Q where
arbitrary :: Gen Q
arbitrary = do
len <- choose (1, 5)
pure $ g len (\ i -> i + choose (0, 1)) -- want different choice for each…
puzzled
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- 4
0
votes
1 answer
error[E0599]: no method named `gen` found for type `&mut G` in the current scope
I'm trying to use the quickcheck crate.
I've implemented Arbitrary for the struct Point {x: u32, y: u32}
impl Arbitrary for Point {
fn arbitrary(g: &mut G) -> Point {
let x = g.gen::();
let y = g.gen::();
…
russelldb
- 21
- 4
0
votes
1 answer
Haskell: Understanding QuickCheck with higher order function
I have the function foo:
foo :: [a] -> (a -> b) -> [b]
foo [] f = []
foo (x:xs) f = foo xs f
And the following two properties that it must satisfy:
prop_1 :: [Int] -> Bool
prop_1 xs = foo xs id == xs
prop_2 :: [Int] -> (Int -> Int) -> (Int ->…
ceno980
- 2,003
- 1
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0
votes
1 answer
How to run a specific number of tests in QuickCheck?
I am trying to learn Haskell and specifically QuickCheck. While Haskell has a lot of information online I am struggling to create some random test with QuickCheck.
For example, I have the following script:
import Test.QuickCheck
whatAge :: Int ->…
Andi Domi
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