time-1.10: test/unix/Test/LocalTime/TimeZone.hs

module Test.LocalTime.TimeZone
    ( testTimeZone
    ) where

import Data.Time
import System.Posix.Env (putEnv)
import Test.Tasty
import Test.Tasty.HUnit

testTimeZone :: TestTree
testTimeZone =
    testCase "getTimeZone respects TZ env var" $ do
        let epoch = UTCTime (ModifiedJulianDay 57000) 0
        putEnv "TZ=UTC+0"
        zone1 <- getTimeZone epoch
        putEnv "TZ=EST+5"
        zone2 <- getTimeZone epoch
        assertBool "zone not changed" $ zone1 /= zone2