agora/agora-test/Spec/Utils.hs

92 lines
2.4 KiB
Haskell

{- |
Module : Spec.Utils
Maintainer : emi@haskell.fyi
Description: Tests for utility functions in 'Agora.Utils'.
Tests for utility functions in 'Agora.Utils'.
-}
module Spec.Utils (tests) where
import Agora.Utils (phalve, pmergeBy, pmsort)
import Data.List (sort)
import Test.Tasty (TestTree)
import Test.Tasty.QuickCheck (testProperty)
tests :: [TestTree]
tests =
[ testProperty "Merge sort sorts a list properly" prop_msortSorted
, testProperty "Two sorted lists are merged into one sorted list" prop_pmergeSorted
, testProperty "Split a list in half as expected" prop_halveProperly
]
--------------------------------------------------------------------------------
prop_msortSorted :: [Integer] -> Bool
prop_msortSorted arr = sorted == expected
where
-- Expected sorted list, using 'Data.List.sort'.
expected :: [Integer]
expected = sort arr
--
psorted :: Term _ (PBuiltinList PInteger)
psorted = pmsort # pconstant arr
sorted :: [Integer]
sorted = plift psorted
prop_pmergeSorted :: [Integer] -> [Integer] -> Bool
prop_pmergeSorted a b = merged == expected
where
-- Sorted list a and b
sa = sort a
sb = sort b
-- Merge two lists which are assumed to be ordered.
merge :: [Integer] -> [Integer] -> [Integer]
merge xs [] = xs
merge [] ys = ys
merge sx@(x : xs) sy@(y : ys)
| x <= y = x : merge xs sy
| otherwise = y : merge sx ys
expected :: [Integer]
expected = merge sa sb
--
pmerged :: Term _ (PBuiltinList PInteger)
pmerged = pmergeBy # plam (#<) # pconstant sa # pconstant sb
merged :: [Integer]
merged = plift pmerged
prop_halveProperly :: [Integer] -> Bool
prop_halveProperly arr = halved == expected
where
-- Halve a list.
halve :: [Integer] -> ([Integer], [Integer])
halve xs = go xs xs
where
go xs [] = ([], xs)
go (x : xs) [_] = ([x], xs)
go (x : xs) (_ : _ : ys) =
let (first, last) =
go xs ys
in (x : first, last)
go [] _ = ([], [])
expected :: ([Integer], [Integer])
expected = halve arr
--
phalved :: Term _ (PPair (PBuiltinList PInteger) (PBuiltinList PInteger))
phalved = phalve # pconstant arr
halved :: ([Integer], [Integer])
halved =
let f = plift $ pmatch phalved $ \(PPair x _) -> x
s = plift $ pmatch phalved $ \(PPair _ x) -> x
in (f, s)