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import Test.QuickCheck
import Text.PrettyPrint.Boxes
#if !MIN_VERSION_base(4,8,0)
import Control.Applicative
#endif
import Control.Monad
import System.Exit (exitFailure, exitSuccess)
#if MIN_VERSION_base(4,11,0)
import Prelude hiding ((<>))
#endif
instance Arbitrary Alignment where
arbitrary = elements [ AlignFirst
, AlignCenter1
, AlignCenter2
, AlignLast
]
instance Arbitrary Box where
arbitrary = sized arbBox
-- A sized generator for boxes. The larger the parameter is, the larger a
-- generated Box is likely to be. This is necessary in order to avoid
-- the tests getting stuck trying to generate ridiculously huge Box values.
arbBox :: Int -> Gen Box
arbBox n =
Box <$> nonnegative <*> nonnegative <*> arbContent n
where
nonnegative = getNonNegative <$> arbitrary
instance Arbitrary Content where
arbitrary = sized arbContent
-- A sized generator for Content values. The larger the parameter is, the
-- larger a generated Content is likely to be. This is necessary in order to
-- avoid the tests getting stuck trying to generate ridiculously huge Content
-- values.
--
-- See also section 3.2 of http://www.cs.tufts.edu/%7Enr/cs257/archive/john-hughes/quick.pdf
arbContent :: Int -> Gen Content
arbContent 0 = pure Blank
arbContent n =
oneof [ pure Blank
, Text <$> arbitrary
, Row <$> halveSize (listOf box)
, Col <$> halveSize (listOf box)
, SubBox <$> arbitrary <*> arbitrary <*> decrementSize box
]
where
decrementSize = scale (\s -> max (s - 1) 0)
halveSize = scale (`quot` 2)
box = arbBox n
-- extensional equivalence for Boxes
b1 ==== b2 = render b1 == render b2
prop_render_text s = render (text s) == (s ++ "\n")
prop_empty_right_id b = b <> nullBox ==== b
prop_empty_left_id b = nullBox <> b ==== b
prop_empty_top_id b = nullBox // b ==== b
prop_empty_bot_id b = b // nullBox ==== b
main = do
quickCheck prop_render_text
quickCheck prop_empty_right_id
quickCheck prop_empty_left_id
quickCheck prop_empty_top_id
quickCheck prop_empty_bot_id
|
