-- | The Assertions module contains assertions for use in HUnit
--   tests. They primarily fill the need for an equality test that
--   works with floating point numbers.
module Assertions
where

import Control.Monad (unless)
import Test.HUnit

import Comparisons
import Point

-- | An HUnit assertion that wraps the almost_equals function. Stolen
--   from the definition of 'assertEqual' in Test\/HUnit\/Base.hs.
assertAlmostEqual :: String -> Double -> Double -> Assertion
assertAlmostEqual preface expected actual =
  unless (actual ~= expected) (assertFailure msg)
    where msg = (if null preface then "" else preface ++ "\n") ++
                "expected: " ++ show expected ++ "\n but got: " ++ show actual


-- | An HUnit assertion that wraps the is_close function. Stolen
--   from the definition of 'assertEqual' in Test\/HUnit\/Base.hs.
assertClose :: String -> Point -> Point -> Assertion
assertClose preface expected actual =
  unless (actual `is_close` expected) (assertFailure msg)
    where msg = (if null preface then "" else preface ++ "\n") ++
                "expected: " ++ show expected ++ "\n but got: " ++ show actual