(.using
 [library
  [lux "*"
   ["_" test {"+" Test}]
   [abstract
    [monad {"+" do}]]
   [data
    ["[0]" bit ("[1]#[0]" equivalence)]]
   [math
    ["[0]" random {"+" Random}]
    [number
     ["n" nat]]]]]
 [\\library
  ["[0]" /]])

(def: .public test
  Test
  (<| (_.covering /._)
      (_.for [/.Arity])
      (do [! random.monad]
        [arity (# ! each (n.% 3) random.nat)]
        ($_ _.and
            (_.cover [/.nullary?]
                     (bit#= (n.= 0 arity) (/.nullary? arity)))
            (_.cover [/.unary?]
                     (bit#= (n.= 1 arity) (/.unary? arity)))
            (_.cover [/.multiary?]
                     (bit#= (n.>= 2 arity) (/.multiary? arity)))
            ))))