MatchSpec.hs

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE ViewPatterns #-}

module Test.Hspec.Expectations.MatchSpec (spec) where

import Test.Hspec
import Test.Hspec.Expectations.Match

spec :: Spec
spec = describe "shouldMatch" $ do
  it "succeeds when a value matches a pattern" $ example $ do
    $([|Just True|] `shouldMatch` [p|Just True|])
    $([|Just True|] `shouldMatch` [p|Just _|])
    $([|Just False|] `shouldMatch` [p|Just _|])

    $([|17 :: Integer|] `shouldMatch` [p|((>= 15) -> True)|])

  it "fails when a value does not match a pattern" $ do
    $([|Just True|] `shouldMatch` [p|Nothing|]) `shouldThrow` anyException
    $([|Nothing|] `shouldMatch` [p|Just True|]) `shouldThrow` anyException

    $([|17 :: Integer|] `shouldMatch` [p|((<= 15) -> True)|]) `shouldThrow` anyException

  it "returns any bindings matched by a successful pattern" $ do
    a <- $([|Just True|] `shouldMatch` [p|Just x|])
    a `shouldBe` True

    (b, c) <- $([|['x', 'y']|] `shouldMatch` [p|[x, y]|])
    b `shouldBe` 'x'
    c `shouldBe` 'y'