(.module:
  [lux #*
   ["_" test (#+ Test)]
   [abstract
    [monad (#+ do)]]
   [math
    ["." random (#+ Random)]]]
  {1
   ["." / (#+ Equivalence)]})

(def: #export (spec (^open "_@.") generator)
  (All [a] (-> (Equivalence a) (Random a) Test))
  (do random.monad
    [left generator
     right generator]
    (<| (_.with-cover [/.Equivalence])
        ($_ _.and
            (_.test "Reflexivity."
                    (_@= left left))
            (_.test "Symmetry."
                    (if (_@= left right)
                      (_@= right left)
                      (not (_@= right left))))))))