Easter.hs

module Test.Calendar.Easter (
    testEaster,
) where

import Data.Time.Calendar
import Data.Time.Calendar.Easter
import Data.Time.Format
import Test.Calendar.EasterRef
import Test.Tasty
import Test.Tasty.HUnit

--
days :: [Day]
days = [ModifiedJulianDay 53000 .. ModifiedJulianDay 53014]

showWithWDay :: Day -> String
showWithWDay = formatTime defaultTimeLocale "%F %A"

testEaster :: TestTree
testEaster =
    testCase "testEaster" $
        let
            ds = unlines $ map (\day -> unwords [showWithWDay day, "->", showWithWDay (sundayAfter day)]) days
            f y =
                unwords
                    [ show y ++ ", Gregorian: moon,"
                    , show (gregorianPaschalMoon y) ++ ": Easter,"
                    , showWithWDay (gregorianEaster y)
                    ]
                    ++ "\n"
            g y =
                unwords
                    [ show y ++ ", Orthodox : moon,"
                    , show (orthodoxPaschalMoon y) ++ ": Easter,"
                    , showWithWDay (orthodoxEaster y)
                    ]
                    ++ "\n"
        in
            assertEqual "" testEasterRef $ ds ++ concatMap (\y -> f y ++ g y) [2000 .. 2020]