kernel: Slug and Lang validated private strings

Both parse through a smart constructor returning result, and both hand-write
t_of_sexp so a malformed value in a data file is rejected at load rather than
silently accepted -- deriving the converter would have bypassed validation.

2 files changed, 42 insertions, 1 deletions

diff --git a/test/test_colitur.ml b/test/test_colitur.ml
index c6c5b91..3341c36 100644
--- a/test/test_colitur.ml
+++ b/test/test_colitur.ml
@@ -1,2 +1,4 @@
 (* Aggregating test runner. Per-module suites live in test_<module>.ml. *)
-let () = Alcotest.run "colitur" [ Test_date.suite; Test_computus.suite; Test_colour.suite ]
+let () =
+  Alcotest.run "colitur"
+    [ Test_date.suite; Test_computus.suite; Test_colour.suite; Test_slug.suite ]
diff --git a/test/test_slug.ml b/test/test_slug.ml
new file mode 100644
index 0000000..af70e9a
--- /dev/null
+++ b/test/test_slug.ml
@@ -0,0 +1,39 @@
+module S = Colitur_kernel.Slug
+module L = Colitur_kernel.Lang
+
+let ok_slug s = match S.of_string s with
+  | Ok t -> t | Error e -> Alcotest.failf "slug %S: %s" s e
+
+let test_slug_accepts () =
+  Alcotest.(check string) "plain" "ef-advent-sunday-1" (S.to_string (ok_slug "ef-advent-sunday-1"));
+  Alcotest.(check string) "digits" "ef-lent-3-monday" (S.to_string (ok_slug "ef-lent-3-monday"))
+
+let test_slug_rejects () =
+  List.iter
+    (fun bad ->
+      Alcotest.(check bool) (Printf.sprintf "reject %S" bad) true (Result.is_error (S.of_string bad)))
+    [ ""; "Ef-Advent"; "ef advent"; "ef_advent"; "-leading"; "trailing-"; "ef/advent" ]
+
+let test_slug_sexp () =
+  let s = ok_slug "ef-easter-sunday" in
+  Alcotest.(check bool) "roundtrip" true (S.equal (S.t_of_sexp (S.sexp_of_t s)) s);
+  (* A malformed slug in a data file must be rejected, not silently accepted. *)
+  Alcotest.check_raises "bad slug in sexp"
+    (Sexplib0.Sexp_conv_error.Of_sexp_error
+       (Failure "slug \"Bad Slug\": only [a-z0-9-] allowed", Sexplib0.Sexp.Atom "Bad Slug"))
+    (fun () -> ignore (S.t_of_sexp (Sexplib0.Sexp.Atom "Bad Slug")))
+
+let test_lang () =
+  Alcotest.(check string) "la" "la" (L.to_string (match L.of_string "la" with
+    | Ok t -> t | Error e -> Alcotest.failf "%s" e));
+  List.iter
+    (fun bad ->
+      Alcotest.(check bool) (Printf.sprintf "reject %S" bad) true (Result.is_error (L.of_string bad)))
+    [ ""; "e"; "eng"; "EN"; "e1" ]
+
+let suite =
+  ( "Slug/Lang",
+    [ Alcotest.test_case "slug accepts" `Quick test_slug_accepts;
+      Alcotest.test_case "slug rejects" `Quick test_slug_rejects;
+      Alcotest.test_case "slug sexp validates" `Quick test_slug_sexp;
+      Alcotest.test_case "lang" `Quick test_lang ] )