Add higher order function test to CameLIGO

src/test/contracts/high-order.mligo

@@ -0,0 +1,46 @@
+(* Test a function which takes another function as an argument *)
+let foobar (i : int) : int =
+  let foo: (int -> int) =
+    fun (i : int) -> i
+  in
+  let bar: ((int -> int) -> int) =
+    fun (f : int -> int) -> f i
+  in
+  bar foo
+
+(* higher order function with more than one argument *)
+let higher2 (i: int) (f: int -> int): int =
+  let ii: int = f i in ii
+
+let foobar2 (i : int) : int =
+  let foo2: (int -> int) =
+    fun (i : int) -> i
+  in
+  higher2 i foo2
+
+let a : int = 0
+
+let foobar3 (i : int) : int =
+  let foo2: (int -> int) =
+    fun (i : int) ->  a + i
+  in
+  higher2 i foo2
+
+let f (i : int) : int = i
+
+let g (i : int) : int = f i
+
+let foobar4 (i : int) : int = g (g i)
+
+let higher3 (i: int) (f: int -> int) (g: int -> int) : int =
+  let ii: int = f (g i) in ii
+
+let foobar5 (i : int) : int =
+  let a : int = 0 in
+  let foo: (int -> int) =
+    fun (i : int) -> a + i
+  in
+  let goo: (int -> int) =
+    fun (i : int) -> foo i
+  in
+  higher3 i foo goo

src/test/integration_tests.ml

@@ -158,6 +158,17 @@ let higher_order () : unit result =
   let%bind _ = expect_eq_n_int program "foobar5" make_expect in
   ok ()
 
+let higher_order_mligo () : unit result =
+  let%bind program = mtype_file "./contracts/high-order.mligo" in
+  let make_expect = fun n -> n in
+  let%bind _ = expect_eq_n_int program "foobar" make_expect in
+  let%bind _ = expect_eq_n_int program "foobar2" make_expect in
+  let%bind _ = expect_eq_n_int program "foobar3" make_expect in
+  let%bind _ = expect_eq_n_int program "foobar4" make_expect in
+  let%bind _ = expect_eq_n_int program "foobar5" make_expect in
+  ok ()
+
+
 let shared_function () : unit result =
   let%bind program = type_file "./contracts/function-shared.ligo" in
   Format.printf "inc\n" ;
@@ -1305,6 +1316,7 @@ let main = test_suite "Integration (End to End)" [
     test "shared function" shared_function ;
     test "shared function (mligo)" shared_function_mligo ;
     test "higher order" higher_order ;
+    test "higher order (mligo)" higher_order_mligo ;
     test "variant" variant ;
     test "variant (mligo)" variant_mligo ;
     test "variant matching" variant_matching ;