src/Assertions.hs

   1 -- | The Assertions module contains assertions for use in HUnit
   2 --   tests. They primarily fill the need for an equality test that
   3 --   works with floating point numbers.
   4 --
   5 module Assertions (
   6   assertAlmostEqual,
   7   assertTrue )
   8 where
   9
  10 import Control.Monad ( unless )
  11 import Test.Tasty.HUnit (
  12   Assertion,
  13   assertBool,
  14   assertFailure )
  15
  16 import Comparisons ( (~=) )
  17
  18
  19 -- | An HUnit assertion that wraps the almost_equals function. Stolen
  20 --   from the definition of 'assertEqual' in Test\/Tasty\/HUnit\/Orig.hs.
  21 --
  22 assertAlmostEqual :: String -- ^ The message prefix
  23                   -> Double -- ^ The expected value
  24                   -> Double -- ^ The actual value
  25                   -> Assertion
  26 assertAlmostEqual preface expected actual =
  27   unless (actual ~= expected) (assertFailure msg)
  28     where msg = (if null preface then "" else preface ++ "\n") ++
  29                 "expected: " ++ show expected ++ "\n but got: " ++ show actual
  30
  31
  32
  33 -- | It's asinine that this doesn't exist already.
  34 --
  35 assertTrue :: String -> Bool -> Assertion
  36 assertTrue = assertBool