Add seq testable

src/alcotest-engine/test.ml

@@ -43,8 +43,7 @@ let testable (type a) (pp : a Fmt.t) (equal : a -> a -> bool) : a testable =
   (module M)
 
 let contramap f t =
-  let pp ppf = (Fmt.using f (pp t)) ppf
-  and equal a b = (equal t (f a) (f b)) in
+  let pp ppf = (Fmt.using f (pp t)) ppf and equal a b = equal t (f a) (f b) in
   testable pp equal
 
 let int32 = testable Fmt.int32 ( = )
@@ -83,6 +82,15 @@ let list e =
   in
   testable (Fmt.Dump.list (pp e)) eq
 
+let seq e =
+  let rec eq s1 s2 =
+    match (Seq.uncons s1, Seq.uncons s2) with
+    | Some (x, xs), Some (y, ys) -> equal e x y && eq xs ys
+    | None, None -> true
+    | _ -> false
+  in
+  testable (Fmt.Dump.seq (pp e)) eq
+
 let slist (type a) (a : a testable) compare =
   let l = list a in
   let eq l1 l2 = equal l (List.sort compare l1) (List.sort compare l2) in

src/alcotest-engine/test.mli

@@ -74,6 +74,9 @@ val unit : unit testable
 val list : 'a testable -> 'a list testable
 (** [list t] tests lists of [t]s. *)
 
+val seq : 'a testable -> 'a Seq.t testable
+(** [seq t] tests sequence of [t]s. *)
+
 val slist : 'a testable -> ('a -> 'a -> int) -> 'a list testable
 (** [slist t comp] tests sorted lists of [t]s. The list are sorted using [comp]. *)