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26 lines
717 B
Haskell
26 lines
717 B
Haskell
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module FailSpec where
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import Polysemy
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import Polysemy.Fail
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import Polysemy.NonDet
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import Test.Hspec
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import Control.Applicative
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semFail :: Member Fail r => Maybe Bool -> Sem r Bool
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semFail mb = do
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Just b <- pure mb
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pure b
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runAlt :: Alternative f => Sem '[Fail, NonDet] a -> f a
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runAlt = run . runNonDet . failToNonDet
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spec :: Spec
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spec = parallel $ do
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describe "MonadFail instance with failToNonDet" $ do
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it "should call empty via fail" $ do
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runAlt (semFail Nothing) `shouldBe` Nothing
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runAlt (semFail Nothing) `shouldBe` []
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it "should work fine for non-failing patterns" $ do
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runAlt (semFail $ Just True) `shouldBe` Just True
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runAlt (semFail $ Just False) `shouldBe` [False]
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