{- Copyright (C) 2012 Dr. Alistair Ward This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. -} {- | [@AUTHOR@] Dr. Alistair Ward [@DESCRIPTION@] Facilities testing of custom implementations of 'Enum'. -} module ToolShed.Test.ReversibleEnum( -- * Functions -- ** Predicates isReversible ) where -- | Checks that composing 'toEnum' & 'fromEnum' is equivalent to the identity. isReversible :: (Eq r, Enum r) => r -> Bool isReversible r = toEnum (fromEnum r) == r