34 lines
1.2 KiB
Haskell
34 lines
1.2 KiB
Haskell
{-# LANGUAGE TemplateHaskell #-}
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module Test where
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import Main (Vertex (Point), fromAngle, move, scale, vertexDistance)
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import Test.QuickCheck (discard, quickCheck, quickCheckAll)
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-- | the largest acceptable difference between two doubles so they are considered equal
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epsilon :: Double
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epsilon = 1e-10
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-- | checks whether the distance of a vertex constructed by 'fromAngle' to the origin is 1
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prop_VertexFromAngleDistance :: Double -> Bool
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prop_VertexFromAngleDistance angle = abs (1 - vertexDistance (fromAngle angle)) < epsilon
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-- | checks whether the distance of a vertex scaled by an factor is multiplied by that factor (absolute).
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prop_VertexScaleDistance :: (Vertex, Double) -> Bool
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prop_VertexScaleDistance (p, s) = abs (abs s * vertexDistance p - vertexDistance (scale s p)) < epsilon
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-- | checks whether moving a vertex by itself equals scaling it by 2
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prop_MoveSelfEqualsScale2 :: Vertex -> Bool
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prop_MoveSelfEqualsScale2 p = move p p == scale 2 p
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-- | checks whether moving a vertex by itself scaled by -1 equals the origin
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prop_MoveNegativeSelfEqualsOrigin :: Vertex -> Bool
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prop_MoveNegativeSelfEqualsOrigin p = move p (scale (-1) p) == Point (0, 0)
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return []
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check = $quickCheckAll
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main :: IO Bool
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main = check
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