unikernel/duniverse/base/test/test_either.ml

@@ -0,0 +1,100 @@
+open! Import
+
+type t = (int, string) Either.t [@@deriving sexp_of]
+
+let f : t = First 0
+let s : t = Second "str"
+
+let%expect_test "First.Monad.map" =
+  let open Either.First.Let_syntax in
+  let inc x =
+    let%map v = x in
+    v + 1
+  in
+  let f' = inc f in
+  let s' = inc s in
+  print_s [%message (f' : t) (s' : t)];
+  [%expect {|
+    ((f' (First  1))
+     (s' (Second str)))
+    |}]
+;;
+
+let%expect_test "Second.Monad.map" =
+  let open Either.Second.Let_syntax in
+  let add x =
+    let%map v = x in
+    String.concat [ v; "1" ]
+  in
+  let f' = add f in
+  let s' = add s in
+  print_s [%message (f' : t) (s' : t)];
+  [%expect {|
+    ((f' (First  0))
+     (s' (Second str1)))
+    |}]
+;;
+
+let%expect_test "First.Monad.bind" =
+  let open Either.First.Let_syntax in
+  let inc x =
+    let%bind v = x in
+    return (v + 1)
+  in
+  let f' = inc f in
+  let s' = inc s in
+  print_s [%message (f' : t) (s' : t)];
+  [%expect {|
+    ((f' (First  1))
+     (s' (Second str)))
+    |}]
+;;
+
+let%expect_test "Second.Monad.bind" =
+  let open Either.Second.Let_syntax in
+  let add x =
+    let%bind v = x in
+    return (String.concat [ v; "1" ])
+  in
+  let f' = add f in
+  let s' = add s in
+  print_s [%message (f' : t) (s' : t)];
+  [%expect {|
+    ((f' (First  0))
+     (s' (Second str1)))
+    |}]
+;;
+
+let%expect_test "First.map2" =
+  let m t1 t2 =
+    let result = Either.First.map2 ~f:(fun x y -> x + y) t1 t2 in
+    print_s [%sexp (result : (int, string) Either.t)]
+  in
+  let foo = "foo" in
+  let bar = "bar" in
+  m (Second foo) (Second bar);
+  [%expect {| (Second foo) |}];
+  m (First 1) (First 2);
+  [%expect {| (First 3) |}];
+  m (Second foo) (First 1);
+  [%expect {| (Second foo) |}];
+  m (First 1) (Second bar);
+  [%expect {| (Second bar) |}]
+;;
+
+let%expect_test "Second.map2" =
+  let m t1 t2 =
+    let result = Either.Second.map2 ~f:(fun x y -> x + y) t1 t2 in
+    print_s [%sexp (result : (string, int) Either.t)]
+  in
+  let foo = "foo" in
+  let bar = "bar" in
+  m (First foo) (First bar);
+  [%expect {| (First foo) |}];
+  m (Second 1) (Second 2);
+  [%expect {| (Second 3) |}];
+  m (First foo) (Second 1);
+  [%expect {| (First foo) |}];
+  m (Second 1) (First bar);
+  [%expect {| (First bar) |}]
+;;