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-- Addition.hs
module Addition where
import Test.Hspec
import Test.QuickCheck
sayHello :: IO ()
sayHello = putStrLn "hello"
main :: IO ()
main = hspec $ do
describe "Addition" $ do
it "1 + 1 is greater than 1" $ do
((1 :: Integer) + 1) > 1 `shouldBe` True
it "2 + 2 is equal to 4" $ do
((2 :: Integer) + 2) `shouldBe` 4
it "15 divided by 3 is 5" $ do
dividedBy (15 :: Integer) 3 `shouldBe` (5,0)
it "22 divided by 5 is 4 remainder 2" $ do
dividedBy (22 :: Integer) 5 `shouldBe` (4,2)
-- Intermission: Short Exercise
it "0 times 1 is 0" $ do
myMult (0 :: Integer) 1 `shouldBe` 0
it "1 times 0 is 0" $ do
myMult (1 :: Integer) 0 `shouldBe` 0
it "2 times 2 is 4" $ do
myMult (2 :: Integer) 2 `shouldBe` 4
it "2 times (-2) is (-4)" $ do
myMult (2 :: Integer) (-2) `shouldBe` (-4)
it "(-2) times 2 is (-4)" $ do
myMult (-2 :: Integer) 2 `shouldBe` (-4)
it "(-2) times (-2) is 4" $ do
myMult (-2 :: Integer) (-2) `shouldBe` 4
-- QuickCheck
it "x + 1 is always greater than x" $ do
property $ \x -> x + 1 > (x :: Int)
dividedBy :: Integral a => a -> a -> (a,a)
dividedBy num denom = go num denom 0
where go n d count
| n < d = (count, n)
| otherwise = go (n - d) d (count + 1)
-- Intermission: Short Exercise
myMult :: (Eq a, Num a) => a -> a -> a
myMult 0 _ = 0
myMult _ 0 = 0
myMult a b =
if abs b == b
then a + myMult a (b - 1)
else negate $ myMult a (negate b)
trivialInt :: Gen Int
trivialInt = return 1
oneThroughThree :: Gen Int
oneThroughThree = elements [1, 2, 3]
oneThroughThree' :: Gen Int
oneThroughThree' = elements [1, 2, 2, 2, 2, 2, 3]
genBool :: Gen Bool
genBool = choose (False, True)
genBool' :: Gen Bool
genBool' = elements [False, True]
genOrdering :: Gen Ordering
genOrdering = elements [LT, EQ, GT]
genChar :: Gen Char
genChar = elements ['a'..'z']
genTuple :: (Arbitrary a, Arbitrary b) => Gen (a,b)
genTuple = do
a <- arbitrary
b <- arbitrary
return (a,b)
genThreeple :: (Arbitrary a, Arbitrary b, Arbitrary c) => Gen (a,b,c)
genThreeple = do
a <- arbitrary
b <- arbitrary
c <- arbitrary
return (a, b, c)
genEither :: (Arbitrary a, Arbitrary b) => Gen (Either a b)
genEither = do
a <- arbitrary
b <- arbitrary
elements [Left a, Right b]
genMaybe :: (Arbitrary a) => Gen (Maybe a)
genMaybe = do
a <- arbitrary
elements [Nothing, Just a]
genMaybe' :: (Arbitrary a) => Gen (Maybe a)
genMaybe' = do
a <- arbitrary
frequency [ (1, return Nothing), (3, return (Just a)) ]
prop_additionGreater :: Int -> Bool
prop_additionGreater x = x + 1 > x
runQc :: IO ()
runQc = quickCheck prop_additionGreater