unikernel/duniverse/base/test/test_option.ml

@@ -0,0 +1,50 @@
+open! Import
+open! Option
+
+let f = ( + )
+let%test _ = [%compare.equal: int t] (merge None None ~f) None
+let%test _ = [%compare.equal: int t] (merge (Some 3) None ~f) (Some 3)
+let%test _ = [%compare.equal: int t] (merge None (Some 3) ~f) (Some 3)
+let%test _ = [%compare.equal: int t] (merge (Some 1) (Some 3) ~f) (Some 4)
+
+let%expect_test "[value_or_thunk]" =
+  let default () =
+    print_endline "THUNK!";
+    0
+  in
+  let value_or_thunk = value_or_thunk ~default in
+  let test t = print_s [%sexp (value_or_thunk t : int)] in
+  (* trigger the thunk *)
+  test None;
+  [%expect {|
+    THUNK!
+    0
+    |}];
+  (* same value, no trigger *)
+  test (Some 0);
+  [%expect {| 0 |}];
+  (* different value *)
+  test (Some 1);
+  [%expect {| 1 |}];
+  (* trigger the thunk again: no memoization *)
+  test None;
+  [%expect {|
+    THUNK!
+    0
+    |}]
+;;
+
+let%expect_test "map2" =
+  let m t1 t2 =
+    let result = Option.map2 ~f:(fun x y -> x + y) t1 t2 in
+    print_s [%sexp (result : int Option.t)]
+  in
+  m None None;
+  [%expect {| () |}];
+  m (Some 1) (Some 2);
+  [%expect {| (3) |}];
+  m None (Some 1);
+  [%expect {| () |}];
+  m (Some 1) None;
+  [%expect {| () |}]
+;;