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41 lines
987 B
Haskell
41 lines
987 B
Haskell
module ViewSpec where
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import Polysemy
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import Polysemy.State
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import Polysemy.Trace
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import Polysemy.View
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import Test.Hspec
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check_see :: Members '[View String, Trace] r => Sem r ()
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check_see = trace . ("saw " ++) =<< see
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spec :: Spec
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spec = parallel $ do
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describe "View effect" $ do
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it "should cache views" $ do
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let a = run
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. runTraceList
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. runState @Int 0
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. viewToState @String @Int (\i -> do
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trace $ "caching " ++ show i
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pure $ show i ) $ do
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check_see
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check_see
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put @Int 3
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trace "it's lazy"
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put @Int 5
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check_see
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check_see
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get @Int
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a `shouldBe` ([ "caching 0"
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, "saw 0"
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, "saw 0"
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, "it's lazy"
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, "caching 5"
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, "saw 5"
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, "saw 5"
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], (5, 5))
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