Solve 'Orthogonal Vectors' kata

src/Orthogonal.hs

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+module Orthogonal where
+
+-- https://www.codewars.com/kata/53670c5867e9f2222f000225/train/haskell
+
+isOrthogonal :: [Int] -> [Int] -> Bool
+isOrthogonal xs ys = (== 0) $ dotProduct xs ys
+
+dotProduct :: [Int] -> [Int] -> Int
+dotProduct [] [] = 0
+dotProduct (x : xs) (y : ys) = x * y + dotProduct xs ys
+
+
+
+-- #againwhatlearned
+-- use `zipWith`
+-- dotProduct = (sum .) . zipWith (*)

test/OrthogonalSpec.hs

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+module OrthogonalSpec where
+
+import Orthogonal (isOrthogonal)
+import Test.HUnit
+import Test.Hspec
+
+runTest :: ([Int], [Int], Bool) -> Expectation
+runTest (xs, ys, expected) =
+  assertEqual (unwords [show xs, show ys]) expected $
+    isOrthogonal xs ys
+
+spec :: Spec
+spec = do
+  describe "Fixed Tests" $ do
+    it "Works for some example tests" $ do
+      mapM_
+        runTest
+        [ ([1, 2], [2, 1], False),
+          ([1, -2], [2, 1], True),
+          ([7, 8], [7, -6], False),
+          ([-13, -26], [-8, 4], True),
+          ([1, 2, 3], [0, -3, 2], True),
+          ([3, 4, 5], [6, 7, -8], False),
+          ([3, -4, -5], [-4, -3, 0], True),
+          ([1, -2, 3, -4], [-4, 3, 2, -1], True),
+          ([2, 4, 5, 6, 7], [-14, -12, 0, 8, 4], True),
+          ([5, 10, 1, 20, 2], [-2, -20, -1, 10, 5], False)
+        ]