Source file testable.ml

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(** [Testable] collects {!Alcotest.testable} definitions for OCaml
    base types. *)

include Alcotest

let exn = testable Fmt.exn ( = )

let map (type a b) (f : b -> a) (t : a testable) : b testable =
  let pp fmt v = pp t fmt (f v) in
  let meq b1 b2 = equal t (f b1) (f b2) in
  testable pp meq

let pair3 (type a b c) (t : (a * (b * c)) testable) : (a * b * c) testable =
  let nest ((x, y, z) : a * b * c) : a * (b * c) = (x, (y, z)) in
  map nest t

let pair4 (type a b c d) (t : (a * (b * (c * d))) testable) :
    (a * b * c * d) testable =
  let nest ((x, y, z, w) : a * b * c * d) : a * (b * (c * d)) =
    (x, (y, (z, w)))
  in
  map nest t

let tuple3 ta tb tc : ('a * 'b * 'c) testable = pair3 (pair ta (pair tb tc))

let tuple4 ta tb tc td : ('a * 'b * 'c * 'd) testable =
  pair4 (pair ta (pair tb (pair tc td)))