# Why not use smallcheck?

**URL:** <https://discourse.haskell.org/t/why-not-use-smallcheck/13860>\
**Category:** Uncategorized\
**Created:** [March 30, 2026, 6:46pm UTC](https://discourse.haskell.org/t/why-not-use-smallcheck/13860 "2026-03-30T18:46:05Z")\
**Posts on this page:** 1\
**Showing post:** 22

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**Author:** ![Bodigrim](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/bodigrim/32/1457_2.png) [@Bodigrim](https://discourse.haskell.org/u/Bodigrim)\
**Post date:** [April 7, 2026, 9:25pm UTC](https://discourse.haskell.org/t/why-not-use-smallcheck/13860/22 "2026-04-07T21:25:55Z")

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> [@turion](#):
>
> For your specific example, for a threshold of 18, `tinycheck` finds the bug after less than 2 million (and more than 200 000) values, which takes 0.3 seconds on my machine. (1.4 seconds for a threshold of 20, still less than 2 million values.) I agree that this is probably less performant than QuickCheck, but still I find it noteable. I achieved it by just writing down the basic idea behind SmallCheck from memory in little time as a library. This says something about the power of the idea.

You asked me about SmallCheck, not about your library. Here is a test suite I based my previous answer on:

```haskell
#!/usr/bin/env cabal
{- cabal:
build-depends: base, tasty, tasty-smallcheck
default-language: GHC2021
-}

import Test.Tasty
import Test.Tasty.SmallCheck
import Data.List (sort)

main = defaultMain $
  -- depth 19 means that we are building lists of length 0..18
  localOption (SmallCheckDepth 19) $
    testProperty "mySort matches the reference implementation" $
      \xs -> mySort xs == sort xs

mySort :: [Int] -> [Int]
mySort xs
  | length xs < 18 = sort xs
  | otherwise = error "explode"

```

This completed ~65000 of tests in 10 minutes on my machine and does not seem to be anywhere near the counterexample. If your library completes 200000+ tests in 0.3 seconds (which is roughly 6000 times faster), that’s a great result, but it does not relate to SmallCheck.

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