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.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\/HUnit\/Base.hs.
  21 assertAlmostEqual :: String -> Double -> Double -> Assertion
  22 assertAlmostEqual preface expected actual =
  23   unless (actual ~= expected) (assertFailure msg)
  24     where msg = (if null preface then "" else preface ++ "\n") ++
  25                 "expected: " ++ show expected ++ "\n but got: " ++ show actual
  26
  27
  28
  29 -- | It's asinine that this doesn't exist already.
  30 assertTrue :: String -> Bool -> Assertion
  31 assertTrue = assertBool